20813506560 has 864 divisors, whose sum is σ = 91760104800. Its totient is φ = 4314562560.

The previous prime is 20813506559. The next prime is 20813506573. The reversal of 20813506560 is 6560531802.

20813506560 is a `hidden beast` number, since 20 + 81 + 3 + 506 + 56 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 49674031 + ... + 49674449.

It is an arithmetic number, because the mean of its divisors is an integer number (106203825).

Almost surely, 2^20813506560 is an apocalyptic number.

20813506560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20813506560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45880052400).

20813506560 is an abundant number, since it is smaller than the sum of its proper divisors (70946598240).

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

20813506560 is a wasteful number, since it uses less digits than its factorization.

20813506560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 477 (or 447 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The spelling of 20813506560 in words is "twenty billion, eight hundred thirteen million, five hundred six thousand, five hundred sixty".