25175490021 has 18 divisors (see below), whose sum is σ = 39971004710. Its totient is φ = 15257872080.

The previous prime is 25175490001. The next prime is 25175490023. The reversal of 25175490021 is 12009457152.

25175490021 is a `hidden beast` number, since 2 + 517 + 54 + 90 + 0 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 24986124900 + 189365121 = 158070^2 + 13761^2 .

It is not a de Polignac number, because 25175490021 - 2⁹ = 25175489509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25175490023) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 11557906 + ... + 11560083.

Almost surely, 2^25175490021 is an apocalyptic number.

It is an amenable number.

25175490021 is a deficient number, since it is larger than the sum of its proper divisors (14795514689).

25175490021 is a wasteful number, since it uses less digits than its factorization.

25175490021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23118017 (or 23118003 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The spelling of 25175490021 in words is "twenty-five billion, one hundred seventy-five million, four hundred ninety thousand, twenty-one".