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Number Explorer

Enter any number (whole or decimal) to see place value, prime factors, divisors and more. No sign-in. More walkthroughs: GCSE maths revision & step-by-step help

This free maths tool shows number facts including: place value, prime factorisation, divisors, sum of digits and digital root; Roman numerals; binary, octal and hexadecimal; sum of two squares and sum of four squares (Lagrange’s theorem); polite numbers (sum of consecutive integers); perfect square, perfect cube, triangular number, pentagonal number, hexagonal number; Fibonacci number, factorial; twin prime, cousin prime, Sophie Germain prime, safe prime; Harshad number, happy number, Kaprekar number; and visualisations (factor tree, number line, prime factor pie).

Number of the day

599

Changes at midnight. No repeats in the last year.

Whole numbers (max 18 digits for full factorisation) or decimals.

Reach the number of the day

Use 6 numbers (1 or 2 large: 25, 50, 75, 100; rest small 1–10) and +, −, ×, ÷ and brackets to hit today’s target.

Select a number to begin