21656989200 has 240 divisors, whose sum is σ = 86493321216. Its totient is φ = 4500134400.

The previous prime is 21656989187. The next prime is 21656989213. The reversal of 21656989200 is 298965612.

It is an interprime number because it is at equal distance from previous prime (21656989187) and next prime (21656989213).

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 21656989200.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 24792 + ... + 209591.

Almost surely, 2^21656989200 is an apocalyptic number.

21656989200 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 21656989200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43246660608).

21656989200 is an abundant number, since it is smaller than the sum of its proper divisors (64836332016).

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

21656989200 is a wasteful number, since it uses less digits than its factorization.

21656989200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234422 (or 234411 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 48.

The spelling of 21656989200 in words is "twenty-one billion, six hundred fifty-six million, nine hundred eighty-nine thousand, two hundred".