225981 has 24 divisors (see below), whose sum is σ = 396864. Its totient is φ = 120960.

The previous prime is 225977. The next prime is 225983. The reversal of 225981 is 189522.

It is not a de Polignac number, because 225981 - 2² = 225977 is a prime.

It is a super-2 number, since 2×225981² = 102134824722, which contains 22 as substring.

225981 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (225983) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 966 + ... + 1176.

It is an arithmetic number, because the mean of its divisors is an integer number (16536).

2²²⁵⁹⁸¹ is an apocalyptic number.

225981 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

225981 is a deficient number, since it is larger than the sum of its proper divisors (170883).

225981 is a wasteful number, since it uses less digits than its factorization.

225981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241 (or 238 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 225981 is about 475.3745891400. The cubic root of 225981 is about 60.9102864681.

The spelling of 225981 in words is "two hundred twenty-five thousand, nine hundred eighty-one".