63815818820 has 48 divisors (see below), whose sum is σ = 148222543728. Its totient is φ = 22925928960.

The previous prime is 63815818739. The next prime is 63815818877. The reversal of 63815818820 is 2881851836.

It can be written as a sum of positive squares in 8 ways, for example, as 2692156996 + 61123661824 = 51886^2 + 247232^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3307211 + ... + 3326450.

It is an arithmetic number, because the mean of its divisors is an integer number (3087969661).

Almost surely, 2^63815818820 is an apocalyptic number.

It is an amenable number.

63815818820 is an abundant number, since it is smaller than the sum of its proper divisors (84406724908).

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

63815818820 is a wasteful number, since it uses less digits than its factorization.

63815818820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6633720 (or 6633718 counting only the distinct ones).

The product of its (nonzero) digits is 737280, while the sum is 50.

The spelling of 63815818820 in words is "sixty-three billion, eight hundred fifteen million, eight hundred eighteen thousand, eight hundred twenty".