20621718720 has 392 divisors, whose sum is σ = 74391591120. Its totient is φ = 5441955840.

The previous prime is 20621718703. The next prime is 20621718757. The reversal of 20621718720 is 2781712602.

20621718720 is a `hidden beast` number, since 2 + 0 + 621 + 7 + 1 + 8 + 7 + 20 = 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 55 ways as a sum of consecutive naturals, for example, 25427115 + ... + 25427925.

Almost surely, 2^20621718720 is an apocalyptic number.

20621718720 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 20621718720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37195795560).

20621718720 is an abundant number, since it is smaller than the sum of its proper divisors (53769872400).

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

20621718720 is an equidigital number, since it uses as much as digits as its factorization.

20621718720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 955 (or 930 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The spelling of 20621718720 in words is "twenty billion, six hundred twenty-one million, seven hundred eighteen thousand, seven hundred twenty".