20561355360 has 768 divisors, whose sum is σ = 89359441920. Its totient is φ = 4299816960.

The previous prime is 20561355349. The next prime is 20561355389. The reversal of 20561355360 is 6355316502.

20561355360 is a `hidden beast` number, since 2 + 0 + 5 + 613 + 5 + 5 + 36 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 75872025 + ... + 75872295.

It is an arithmetic number, because the mean of its divisors is an integer number (116353440).

Almost surely, 2^20561355360 is an apocalyptic number.

20561355360 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 20561355360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44679720960).

20561355360 is an abundant number, since it is smaller than the sum of its proper divisors (68798086560).

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

20561355360 is a wasteful number, since it uses less digits than its factorization.

20561355360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 508 (or 494 counting only the distinct ones).

The product of its (nonzero) digits is 81000, while the sum is 36.

The spelling of 20561355360 in words is "twenty billion, five hundred sixty-one million, three hundred fifty-five thousand, three hundred sixty".