20520972855 has 12 divisors (see below), whose sum is σ = 35569686360. Its totient is φ = 10944518832.

The previous prime is 20520972839. The next prime is 20520972863. The reversal of 20520972855 is 55827902502.

20520972855 is a `hidden beast` number, since 2 + 0 + 520 + 9 + 72 + 8 + 55 = 666.

It is not a de Polignac number, because 20520972855 - 2⁴ = 20520972839 is a prime.

It is a super-2 number, since 2×20520972855² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 456021619 = 20520972855 / (2 + 0 + 5 + 2 + 0 + 9 + 7 + 2 + 8 + 5 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 20520972855.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 228010765 + ... + 228010854.

It is an arithmetic number, because the mean of its divisors is an integer number (2964140530).

Almost surely, 2^20520972855 is an apocalyptic number.

20520972855 is a deficient number, since it is larger than the sum of its proper divisors (15048713505).

20520972855 is a wasteful number, since it uses less digits than its factorization.

20520972855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 456021630 (or 456021627 counting only the distinct ones).

The product of its (nonzero) digits is 504000, while the sum is 45.

The spelling of 20520972855 in words is "twenty billion, five hundred twenty million, nine hundred seventy-two thousand, eight hundred fifty-five".