20513951568 has 160 divisors (see below), whose sum is σ = 65289571200. Its totient is φ = 6114355200.

The previous prime is 20513951543. The next prime is 20513951573. The reversal of 20513951568 is 86515931502.

20513951568 is a `hidden beast` number, since 2 + 0 + 5 + 1 + 39 + 51 + 568 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 254488 + ... + 325256.

It is an arithmetic number, because the mean of its divisors is an integer number (408059820).

Almost surely, 2^20513951568 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20513951568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32644785600).

20513951568 is an abundant number, since it is smaller than the sum of its proper divisors (44775619632).

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

20513951568 is a wasteful number, since it uses less digits than its factorization.

20513951568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70858 (or 70846 counting only the distinct ones).

The product of its (nonzero) digits is 324000, while the sum is 45.

The spelling of 20513951568 in words is "twenty billion, five hundred thirteen million, nine hundred fifty-one thousand, five hundred sixty-eight".