639630719865 has 48 divisors (see below), whose sum is σ = 1146349241856. Its totient is φ = 329705452800.

The previous prime is 639630719863. The next prime is 639630719873. The reversal of 639630719865 is 568917036936.

639630719865 is a `hidden beast` number, since 6 + 396 + 30 + 71 + 98 + 65 = 666.

It is not a de Polignac number, because 639630719865 - 2¹ = 639630719863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (639630719863) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1422601 + ... + 1817430.

It is an arithmetic number, because the mean of its divisors is an integer number (23882275872).

Almost surely, 2^639630719865 is an apocalyptic number.

It is an amenable number.

639630719865 is a deficient number, since it is larger than the sum of its proper divisors (506718521991).

639630719865 is a wasteful number, since it uses less digits than its factorization.

639630719865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3240190 (or 3240187 counting only the distinct ones).

The product of its (nonzero) digits is 44089920, while the sum is 63.

The spelling of 639630719865 in words is "six hundred thirty-nine billion, six hundred thirty million, seven hundred nineteen thousand, eight hundred sixty-five".