25371516661 has 2 divisors, whose sum is σ = 25371516662. Its totient is φ = 25371516660.

The previous prime is 25371516659. The next prime is 25371516689. The reversal of 25371516661 is 16661517352.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23891575761 + 1479940900 = 154569^2 + 38470^2 .

It is a cyclic number.

It is not a de Polignac number, because 25371516661 - 2¹ = 25371516659 is a prime.

Together with 25371516659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25371516691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12685758330 + 12685758331.

It is an arithmetic number, because the mean of its divisors is an integer number (12685758331).

Almost surely, 2^25371516661 is an apocalyptic number.

It is an amenable number.

25371516661 is a deficient number, since it is larger than the sum of its proper divisors (1).

25371516661 is an equidigital number, since it uses as much as digits as its factorization.

25371516661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 226800, while the sum is 43.

The spelling of 25371516661 in words is "twenty-five billion, three hundred seventy-one million, five hundred sixteen thousand, six hundred sixty-one".