639496864 has 24 divisors (see below), whose sum is σ = 1302425460. Its totient is φ = 308722176.

The previous prime is 639496859. The next prime is 639496867. The reversal of 639496864 is 468694936.

It can be written as a sum of positive squares in 2 ways, for example, as 576960400 + 62536464 = 24020^2 + 7908^2 .

It is not an unprimeable number, because it can be changed into a prime (639496867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 343629 + ... + 345484.

Almost surely, 2^639496864 is an apocalyptic number.

It is an amenable number.

639496864 is an abundant number, since it is smaller than the sum of its proper divisors (662928596).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

639496864 is a wasteful number, since it uses less digits than its factorization.

639496864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 689152 (or 689144 counting only the distinct ones).

The product of its digits is 6718464, while the sum is 55.

The square root of 639496864 is about 25288.2752278600. The cubic root of 639496864 is about 861.5479889645.

It can be divided in two parts, 639 and 496864, that added together give a triangular number (497503 = T₉₉₇).

The spelling of 639496864 in words is "six hundred thirty-nine million, four hundred ninety-six thousand, eight hundred sixty-four".