25521745761 has 20 divisors (see below), whose sum is σ = 38129526292. Its totient is φ = 17012511648.

The previous prime is 25521745721. The next prime is 25521745787. The reversal of 25521745761 is 16754712552.

25521745761 is a `hidden beast` number, since 2 + 5 + 5 + 2 + 1 + 74 + 576 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1040449536 + 24481296225 = 32256^2 + 156465^2 .

It is not a de Polignac number, because 25521745761 - 2²³ = 25513357153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25521745721) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1089771 + ... + 1112943.

Almost surely, 2^25521745761 is an apocalyptic number.

It is an amenable number.

25521745761 is a deficient number, since it is larger than the sum of its proper divisors (12607780531).

25521745761 is a wasteful number, since it uses less digits than its factorization.

25521745761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36782 (or 36773 counting only the distinct ones).

The product of its digits is 588000, while the sum is 45.

The spelling of 25521745761 in words is "twenty-five billion, five hundred twenty-one million, seven hundred forty-five thousand, seven hundred sixty-one".