639095657 has 2 divisors, whose sum is σ = 639095658. Its totient is φ = 639095656.

The previous prime is 639095651. The next prime is 639095689. The reversal of 639095657 is 756590936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 499477801 + 139617856 = 22349^2 + 11816^2 .

It is a cyclic number.

It is not a de Polignac number, because 639095657 - 2⁶ = 639095593 is a prime.

It is not a weakly prime, because it can be changed into another prime (639095651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319547828 + 319547829.

It is an arithmetic number, because the mean of its divisors is an integer number (319547829).

Almost surely, 2^639095657 is an apocalyptic number.

It is an amenable number.

639095657 is a deficient number, since it is larger than the sum of its proper divisors (1).

639095657 is an equidigital number, since it uses as much as digits as its factorization.

639095657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1530900, while the sum is 50.

The square root of 639095657 is about 25280.3413149427. The cubic root of 639095657 is about 861.3677788571.

The spelling of 639095657 in words is "six hundred thirty-nine million, ninety-five thousand, six hundred fifty-seven".