25537581261 has 24 divisors (see below), whose sum is σ = 38269917504. Its totient is φ = 17017892640.

The previous prime is 25537581227. The next prime is 25537581323. The reversal of 25537581261 is 16218573552.

25537581261 is a `hidden beast` number, since 2 + 5 + 5 + 3 + 7 + 581 + 2 + 61 = 666.

It is not a de Polignac number, because 25537581261 - 2²³ = 25529192653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25537581211) 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, 591760 + ... + 633446.

It is an arithmetic number, because the mean of its divisors is an integer number (1594579896).

Almost surely, 2^25537581261 is an apocalyptic number.

It is an amenable number.

25537581261 is a deficient number, since it is larger than the sum of its proper divisors (12732336243).

25537581261 is an equidigital number, since it uses as much as digits as its factorization.

25537581261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44223 (or 44211 counting only the distinct ones).

The product of its digits is 504000, while the sum is 45.

The spelling of 25537581261 in words is "twenty-five billion, five hundred thirty-seven million, five hundred eighty-one thousand, two hundred sixty-one".