25561386457 has 2 divisors, whose sum is σ = 25561386458. Its totient is φ = 25561386456.

The previous prime is 25561386449. The next prime is 25561386517. The reversal of 25561386457 is 75468316552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24957996361 + 603390096 = 157981^2 + 24564^2 .

It is a cyclic number.

It is not a de Polignac number, because 25561386457 - 2³ = 25561386449 is a prime.

It is not a weakly prime, because it can be changed into another prime (25561380457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12780693228 + 12780693229.

It is an arithmetic number, because the mean of its divisors is an integer number (12780693229).

Almost surely, 2^25561386457 is an apocalyptic number.

It is an amenable number.

25561386457 is a deficient number, since it is larger than the sum of its proper divisors (1).

25561386457 is an equidigital number, since it uses as much as digits as its factorization.

25561386457 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048000, while the sum is 52.

The spelling of 25561386457 in words is "twenty-five billion, five hundred sixty-one million, three hundred eighty-six thousand, four hundred fifty-seven".