25139585021 has 4 divisors (see below), whose sum is σ = 25483962972. Its totient is φ = 24795207072.

The previous prime is 25139584957. The next prime is 25139585033. The reversal of 25139585021 is 12058593152.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13147144921 + 11992440100 = 114661^2 + 109510^2 .

It is a cyclic number.

It is not a de Polignac number, because 25139585021 - 2⁶ = 25139584957 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 25139585021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25139585621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 172188866 + ... + 172189011.

It is an arithmetic number, because the mean of its divisors is an integer number (6370990743).

Almost surely, 2^25139585021 is an apocalyptic number.

It is an amenable number.

25139585021 is a deficient number, since it is larger than the sum of its proper divisors (344377951).

25139585021 is an equidigital number, since it uses as much as digits as its factorization.

25139585021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344377950.

The product of its (nonzero) digits is 108000, while the sum is 41.

The spelling of 25139585021 in words is "twenty-five billion, one hundred thirty-nine million, five hundred eighty-five thousand, twenty-one".