25611894521 has 4 divisors (see below), whose sum is σ = 25674515700. Its totient is φ = 25549273344.

The previous prime is 25611894499. The next prime is 25611894523. The reversal of 25611894521 is 12549811652.

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 24902418025 + 709476496 = 157805^2 + 26636^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25611894521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25611894523) 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, 31309976 + ... + 31310793.

It is an arithmetic number, because the mean of its divisors is an integer number (6418628925).

Almost surely, 2^25611894521 is an apocalyptic number.

It is an amenable number.

25611894521 is a deficient number, since it is larger than the sum of its proper divisors (62621179).

25611894521 is an equidigital number, since it uses as much as digits as its factorization.

25611894521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62621178.

The product of its digits is 172800, while the sum is 44.

The spelling of 25611894521 in words is "twenty-five billion, six hundred eleven million, eight hundred ninety-four thousand, five hundred twenty-one".