639985515264 has 432 divisors, whose sum is σ = 1957345388544. Its totient is φ = 208496332800.

The previous prime is 639985515241. The next prime is 639985515283. The reversal of 639985515264 is 462515589936.

639985515264 is a `hidden beast` number, since 6 + 3 + 9 + 98 + 5 + 515 + 26 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (432).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 724784967 + ... + 724785849.

Almost surely, 2^639985515264 is an apocalyptic number.

639985515264 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

639985515264 is the 505959-th heptagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639985515264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (978672694272).

639985515264 is an abundant number, since it is smaller than the sum of its proper divisors (1317359873280).

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

639985515264 is an equidigital number, since it uses as much as digits as its factorization.

639985515264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1166 (or 1140 counting only the distinct ones).

The product of its digits is 69984000, while the sum is 63.

The spelling of 639985515264 in words is "six hundred thirty-nine billion, nine hundred eighty-five million, five hundred fifteen thousand, two hundred sixty-four".