639400345601 has 2 divisors, whose sum is σ = 639400345602. Its totient is φ = 639400345600.

The previous prime is 639400345583. The next prime is 639400345637. The reversal of 639400345601 is 106543004936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 364965807376 + 274434538225 = 604124^2 + 523865^2 .

It is a cyclic number.

It is not a de Polignac number, because 639400345601 - 2¹⁸ = 639400083457 is a prime.

It is not a weakly prime, because it can be changed into another prime (639400344601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319700172800 + 319700172801.

It is an arithmetic number, because the mean of its divisors is an integer number (319700172801).

Almost surely, 2^639400345601 is an apocalyptic number.

It is an amenable number.

639400345601 is a deficient number, since it is larger than the sum of its proper divisors (1).

639400345601 is an equidigital number, since it uses as much as digits as its factorization.

639400345601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 233280, while the sum is 41.

The spelling of 639400345601 in words is "six hundred thirty-nine billion, four hundred million, three hundred forty-five thousand, six hundred one".