21656868480 has 1024 divisors, whose sum is σ = 89943436800. Its totient is φ = 4876664832.

The previous prime is 21656868437. The next prime is 21656868487. The reversal of 21656868480 is 8486865612.

21656868480 is a `hidden beast` number, since 2 + 16 + 568 + 68 + 4 + 8 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (21656868487) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 202400587 + ... + 202400693.

Almost surely, 2^21656868480 is an apocalyptic number.

21656868480 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 21656868480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44971718400).

21656868480 is an abundant number, since it is smaller than the sum of its proper divisors (68286568320).

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

21656868480 is a wasteful number, since it uses less digits than its factorization.

21656868480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218 (or 200 counting only the distinct ones).

The product of its (nonzero) digits is 4423680, while the sum is 54.

The spelling of 21656868480 in words is "twenty-one billion, six hundred fifty-six million, eight hundred sixty-eight thousand, four hundred eighty".