21087928800 has 576 divisors, whose sum is σ = 81866635200. Its totient is φ = 5285191680.

The previous prime is 21087928789. The next prime is 21087928831. The reversal of 21087928800 is 882978012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 29742846 + ... + 29743554.

It is an arithmetic number, because the mean of its divisors is an integer number (142129575).

Almost surely, 2^21087928800 is an apocalyptic number.

21087928800 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 21087928800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40933317600).

21087928800 is an abundant number, since it is smaller than the sum of its proper divisors (60778706400).

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

21087928800 is an equidigital number, since it uses as much as digits as its factorization.

21087928800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 767 (or 736 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The spelling of 21087928800 in words is "twenty-one billion, eighty-seven million, nine hundred twenty-eight thousand, eight hundred".