25631696681 has 2 divisors, whose sum is σ = 25631696682. Its totient is φ = 25631696680.

The previous prime is 25631696663. The next prime is 25631696743. The reversal of 25631696681 is 18669613652.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24342240400 + 1289456281 = 156020^2 + 35909^2 .

It is a cyclic number.

It is not a de Polignac number, because 25631696681 - 2⁶ = 25631696617 is a prime.

It is a super-2 number, since 2×25631696681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (25631696611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12815848340 + 12815848341.

It is an arithmetic number, because the mean of its divisors is an integer number (12815848341).

Almost surely, 2^25631696681 is an apocalyptic number.

It is an amenable number.

25631696681 is a deficient number, since it is larger than the sum of its proper divisors (1).

25631696681 is an equidigital number, since it uses as much as digits as its factorization.

25631696681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2799360, while the sum is 53.

The spelling of 25631696681 in words is "twenty-five billion, six hundred thirty-one million, six hundred ninety-six thousand, six hundred eighty-one".