25642436639 has 2 divisors, whose sum is σ = 25642436640. Its totient is φ = 25642436638.

The previous prime is 25642436629. The next prime is 25642436653. The reversal of 25642436639 is 93663424652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 25642436639 - 2⁸ = 25642436383 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25642436629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12821218319 + 12821218320.

It is an arithmetic number, because the mean of its divisors is an integer number (12821218320).

Almost surely, 2^25642436639 is an apocalyptic number.

25642436639 is a deficient number, since it is larger than the sum of its proper divisors (1).

25642436639 is an equidigital number, since it uses as much as digits as its factorization.

25642436639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5598720, while the sum is 50.

The spelling of 25642436639 in words is "twenty-five billion, six hundred forty-two million, four hundred thirty-six thousand, six hundred thirty-nine".