225581 has 2 divisors, whose sum is σ = 225582. Its totient is φ = 225580.

The previous prime is 225569. The next prime is 225583. The reversal of 225581 is 185522.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 198025 + 27556 = 445^2 + 166^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-225581 is a prime.

It is a super-2 number, since 2×225581² = 101773575122, which contains 22 as substring.

Together with 225583, it forms a pair of twin primes.

It is a Chen prime.

It is a nialpdrome in base 12.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 225581.

It is not a weakly prime, because it can be changed into another prime (225583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 112790 + 112791.

It is an arithmetic number, because the mean of its divisors is an integer number (112791).

2²²⁵⁵⁸¹ is an apocalyptic number.

It is an amenable number.

225581 is a deficient number, since it is larger than the sum of its proper divisors (1).

225581 is an equidigital number, since it uses as much as digits as its factorization.

225581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 800, while the sum is 23.

The square root of 225581 is about 474.9536819523. The cubic root of 225581 is about 60.8743269493.

The spelling of 225581 in words is "two hundred twenty-five thousand, five hundred eighty-one".