225720581 has 2 divisors, whose sum is σ = 225720582. Its totient is φ = 225720580.

The previous prime is 225720559. The next prime is 225720623. The reversal of 225720581 is 185027522.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 134212225 + 91508356 = 11585^2 + 9566^2 .

It is a cyclic number.

It is not a de Polignac number, because 225720581 - 2¹⁴ = 225704197 is a prime.

It is a super-2 number, since 2×225720581² = 101899561373955122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (225720511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 112860290 + 112860291.

It is an arithmetic number, because the mean of its divisors is an integer number (112860291).

Almost surely, 2^225720581 is an apocalyptic number.

It is an amenable number.

225720581 is a deficient number, since it is larger than the sum of its proper divisors (1).

225720581 is an equidigital number, since it uses as much as digits as its factorization.

225720581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11200, while the sum is 32.

The square root of 225720581 is about 15024.0001664004. Note that the first 3 decimals coincide. The cubic root of 225720581 is about 608.8687993840.

The spelling of 225720581 in words is "two hundred twenty-five million, seven hundred twenty thousand, five hundred eighty-one".