21010564800 has 504 divisors, whose sum is σ = 80567082960. Its totient is φ = 5175705600.

The previous prime is 21010564711. The next prime is 21010564831. The reversal of 21010564800 is 846501012.

21010564800 is a `hidden beast` number, since 2 + 1 + 0 + 10 + 5 + 648 + 0 + 0 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 11216664 + ... + 11218536.

Almost surely, 2^21010564800 is an apocalyptic number.

21010564800 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 21010564800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40283541480).

21010564800 is an abundant number, since it is smaller than the sum of its proper divisors (59556518160).

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

21010564800 is a wasteful number, since it uses less digits than its factorization.

21010564800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1961 (or 1943 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The spelling of 21010564800 in words is "twenty-one billion, ten million, five hundred sixty-four thousand, eight hundred".