639971207624 has 96 divisors (see below), whose sum is σ = 1426559688000. Its totient is φ = 263641161600.

The previous prime is 639971207543. The next prime is 639971207627. The reversal of 639971207624 is 426702179936.

It is a Harshad number since it is a multiple of its sum of digits (56).

It is a self number, because there is not a number n which added to its sum of digits gives 639971207624.

It is not an unprimeable number, because it can be changed into a prime (639971207627) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7978679 + ... + 8058489.

It is an arithmetic number, because the mean of its divisors is an integer number (14859996750).

Almost surely, 2^639971207624 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639971207624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (713279844000).

639971207624 is an abundant number, since it is smaller than the sum of its proper divisors (786588480376).

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

639971207624 is a wasteful number, since it uses less digits than its factorization.

639971207624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80035 (or 80000 counting only the distinct ones).

The product of its (nonzero) digits is 6858432, while the sum is 56.

The spelling of 639971207624 in words is "six hundred thirty-nine billion, nine hundred seventy-one million, two hundred seven thousand, six hundred twenty-four".