63799721636 has 24 divisors (see below), whose sum is σ = 129691240896. Its totient is φ = 26894495520.

The previous prime is 63799721621. The next prime is 63799721641. The reversal of 63799721636 is 63612799736.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18675026 + ... + 18678441.

It is an arithmetic number, because the mean of its divisors is an integer number (5403801704).

Almost surely, 2^63799721636 is an apocalyptic number.

It is an amenable number.

63799721636 is an abundant number, since it is smaller than the sum of its proper divisors (65891519260).

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

63799721636 is a wasteful number, since it uses less digits than its factorization.

63799721636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37353539 (or 37353537 counting only the distinct ones).

The product of its digits is 15431472, while the sum is 59.

The spelling of 63799721636 in words is "sixty-three billion, seven hundred ninety-nine million, seven hundred twenty-one thousand, six hundred thirty-six".