25645514521 has 12 divisors (see below), whose sum is σ = 28196053732. Its totient is φ = 23308164000.

The previous prime is 25645514497. The next prime is 25645514527. The reversal of 25645514521 is 12541554652.

It can be written as a sum of positive squares in 2 ways, for example, as 24346921225 + 1298593296 = 156035^2 + 36036^2 .

It is a de Polignac number, because none of the positive numbers 2^k-25645514521 is a prime.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (25645514527) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 490711 + ... + 540451.

Almost surely, 2^25645514521 is an apocalyptic number.

It is an amenable number.

25645514521 is a deficient number, since it is larger than the sum of its proper divisors (2550539211).

25645514521 is a wasteful number, since it uses less digits than its factorization.

25645514521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54024 (or 54013 counting only the distinct ones).

The product of its digits is 240000, while the sum is 40.

The spelling of 25645514521 in words is "twenty-five billion, six hundred forty-five million, five hundred fourteen thousand, five hundred twenty-one".