639670694400 has 960 divisors, whose sum is σ = 2411202816000. Its totient is φ = 166053888000.

The previous prime is 639670694389. The next prime is 639670694489. The reversal of 639670694400 is 4496076936.

639670694400 is a `hidden beast` number, since 63 + 96 + 7 + 0 + 6 + 94 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (960).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3214425501 + ... + 3214425699.

It is an arithmetic number, because the mean of its divisors is an integer number (2511669600).

Almost surely, 2^639670694400 is an apocalyptic number.

639670694400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639670694400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1205601408000).

639670694400 is an abundant number, since it is smaller than the sum of its proper divisors (1771532121600).

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

639670694400 is a wasteful number, since it uses less digits than its factorization.

639670694400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438 (or 411 counting only the distinct ones).

The product of its (nonzero) digits is 5878656, while the sum is 54.

The spelling of 639670694400 in words is "six hundred thirty-nine billion, six hundred seventy million, six hundred ninety-four thousand, four hundred".