20815333864 has 24 divisors (see below), whose sum is σ = 42261904710. Its totient is φ = 9607076544.

The previous prime is 20815333849. The next prime is 20815333879. The reversal of 20815333864 is 46833351802.

It is an interprime number because it is at equal distance from previous prime (20815333849) and next prime (20815333879).

It can be written as a sum of positive squares in 3 ways, for example, as 11654929764 + 9160404100 = 107958^2 + 95710^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20815333864.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7696627 + ... + 7699330.

Almost surely, 2^20815333864 is an apocalyptic number.

It is an amenable number.

20815333864 is an abundant number, since it is smaller than the sum of its proper divisors (21446570846).

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

20815333864 is a wasteful number, since it uses less digits than its factorization.

20815333864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15395989 (or 15395972 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 43.

The spelling of 20815333864 in words is "twenty billion, eight hundred fifteen million, three hundred thirty-three thousand, eight hundred sixty-four".