21021264460800 has 1056 divisors, whose sum is σ = 79467251865600. Its totient is φ = 5443117056000.

The previous prime is 21021264460717. The next prime is 21021264460829. The reversal of 21021264460800 is 806446212012.

21021264460800 is a `hidden beast` number, since 2 + 1 + 0 + 2 + 1 + 2 + 6 + 44 + 608 + 0 + 0 = 666.

It is a super-2 number, since 2×21021264460800² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3330889645 + ... + 3330895955.

Almost surely, 2^{21021264460800} is an apocalyptic number.

21021264460800 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 21021264460800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39733625932800).

21021264460800 is an abundant number, since it is smaller than the sum of its proper divisors (58445987404800).

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

21021264460800 is a wasteful number, since it uses less digits than its factorization.

21021264460800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6490 (or 6461 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The spelling of 21021264460800 in words is "twenty-one trillion, twenty-one billion, two hundred sixty-four million, four hundred sixty thousand, eight hundred".