639720862089636 has 24 divisors (see below), whose sum is σ = 1492686677682144. Its totient is φ = 213239620771840.

The previous prime is 639720862089607. The next prime is 639720862089637. The reversal of 639720862089636 is 636980268027936.

It is a super-2 number, since 2×639720862089636² (a number of 30 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (639720862089637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79317510 + ... + 87009821.

It is an arithmetic number, because the mean of its divisors is an integer number (62195278236756).

Almost surely, 2^{639720862089636} is an apocalyptic number.

It is an amenable number.

639720862089636 is an abundant number, since it is smaller than the sum of its proper divisors (852965815592508).

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

639720862089636 is a wasteful number, since it uses less digits than its factorization.

639720862089636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166647851 (or 166647849 counting only the distinct ones).

The product of its (nonzero) digits is 1693052928, while the sum is 75.

The spelling of 639720862089636 in words is "six hundred thirty-nine trillion, seven hundred twenty billion, eight hundred sixty-two million, eighty-nine thousand, six hundred thirty-six".