21568236900 has 432 divisors, whose sum is σ = 74688969600. Its totient is φ = 4790016000.

The previous prime is 21568236869. The next prime is 21568236917. The reversal of 21568236900 is 963286512.

It is a super-2 number, since 2×21568236900² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 108383001 + ... + 108383199.

Almost surely, 2^21568236900 is an apocalyptic number.

21568236900 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 21568236900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37344484800).

21568236900 is an abundant number, since it is smaller than the sum of its proper divisors (53120732700).

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

21568236900 is a wasteful number, since it uses less digits than its factorization.

21568236900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404 (or 390 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 42.

The spelling of 21568236900 in words is "twenty-one billion, five hundred sixty-eight million, two hundred thirty-six thousand, nine hundred".