21521224800 has 1152 divisors, whose sum is σ = 89094297600. Its totient is φ = 4985487360.

The previous prime is 21521224799. The next prime is 21521224819. The reversal of 21521224800 is 842212512.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 457898377 + ... + 457898423.

It is an arithmetic number, because the mean of its divisors is an integer number (77338800).

Almost surely, 2^21521224800 is an apocalyptic number.

21521224800 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 21521224800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44547148800).

21521224800 is an abundant number, since it is smaller than the sum of its proper divisors (67573072800).

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

21521224800 is a wasteful number, since it uses less digits than its factorization.

21521224800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165 (or 146 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 27.

The spelling of 21521224800 in words is "twenty-one billion, five hundred twenty-one million, two hundred twenty-four thousand, eight hundred".