Number Theory

Armstrong Number Calculator

Test whether a non-negative integer equals the sum of its digits raised to its digit count.

Number Theory

Enter integer data

Exact private calculation in your browser

Enter base-10 integers only. General integer fields accept up to 100 digits; factorization-based tools explicitly limit magnitudes to 10¹², bounded searches to 100,000 or 1,000,000 as labelled, and primality tests to unsigned 64-bit integers. Inputs stay on this device.

Result

Enter valid values to see the result.

Your entries are calculated in this browser and are not submitted to 365CALCS.COM.

Quick guide

How to use this calculator

  1. Choose the required modular or symbol mode when one is available.
  2. Enter the labelled base-10 integers or comma-separated integer lists.
  3. Read the exact classification, residue, factorization, solution family, or bounded sequence.

Calculation method

Apply the exact integer algorithm

For d digits, n=Σ digitᵈ.

The engine uses exact BigInt arithmetic and explicit work limits. Undefined inverses, incompatible congruences, invalid prime assumptions, and unsupported exhaustive searches return an error or a mathematically distinct no-solution result.

Worked example

Worked example

153=1³+5³+3³.

For d digits, n=Σ digitᵈ.

Supported inputs

Precision and limits

Exact arithmetic

Integer arithmetic and displayed residues are exact. No floating-point conversion is used in the calculation engine.

Work limits

Factorization and divisor tools support positive inputs through 10¹². Enumeration tools label limits of 100,000 or 1,000,000; deterministic primality testing supports n<2⁶⁴. General non-enumerated integer fields accept up to 100 digits.

Conventions

Modulo results use the least non-negative residue. Divisors are positive unless a theorem explicitly uses signed or directed integers. Primality begins at 2.

Scope

Exploratory calculators compute only the entered bounded case. A Goldbach pair, Carmichael classification, or other result does not claim to settle a general conjecture beyond that input.