20513173972 has 12 divisors (see below), whose sum is σ = 35901735156. Its totient is φ = 10255535360.

The previous prime is 20513173957. The next prime is 20513173973. The reversal of 20513173972 is 27937131502.

It can be written as a sum of positive squares in 2 ways, for example, as 42432196 + 20470741776 = 6514^2 + 143076^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20513173973) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 218173 + ... + 297700.

It is an arithmetic number, because the mean of its divisors is an integer number (2991811263).

Almost surely, 2^20513173972 is an apocalyptic number.

It is an amenable number.

20513173972 is a deficient number, since it is larger than the sum of its proper divisors (15388561184).

20513173972 is a wasteful number, since it uses less digits than its factorization.

20513173972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 525818 (or 525816 counting only the distinct ones).

The product of its (nonzero) digits is 79380, while the sum is 40.

The spelling of 20513173972 in words is "twenty billion, five hundred thirteen million, one hundred seventy-three thousand, nine hundred seventy-two".