636623791720 has 64 divisors (see below), whose sum is σ = 1670441472000. Its totient is φ = 218271009600.

The previous prime is 636623791637. The next prime is 636623791721. The reversal of 636623791720 is 27197326636.

It is not an unprimeable number, because it can be changed into a prime (636623791721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23186856 + ... + 23214295.

It is an arithmetic number, because the mean of its divisors is an integer number (26100648000).

Almost surely, 2^636623791720 is an apocalyptic number.

It is an amenable number.

636623791720 is an abundant number, since it is smaller than the sum of its proper divisors (1033817680280).

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

636623791720 is a wasteful number, since it uses less digits than its factorization.

636623791720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46401183 (or 46401165 counting only the distinct ones).

The product of its (nonzero) digits is 3429216, while the sum is 52.

The spelling of 636623791720 in words is "six hundred thirty-six billion, six hundred twenty-three million, seven hundred ninety-one thousand, seven hundred twenty".