21025504813824 has 1296 divisors, whose sum is σ = 75396684199200. Its totient is φ = 5824102072320.

The previous prime is 21025504813811. The next prime is 21025504813837. The reversal of 21025504813824 is 42831840552012.

21025504813824 is a `hidden beast` number, since 2 + 1 + 0 + 2 + 5 + 504 + 8 + 138 + 2 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (21025504813811) and next prime (21025504813837).

It is a tau number, because it is divible by the number of its divisors (1296).

It is a super-2 number, since 2×21025504813824² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21025504813824.

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, 13573598202 + ... + 13573599750.

Almost surely, 2^{21025504813824} is an apocalyptic number.

21025504813824 is a gapful number since it is divisible by the number (24) 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 21025504813824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37698342099600).

21025504813824 is an abundant number, since it is smaller than the sum of its proper divisors (54371179385376).

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

21025504813824 is an equidigital number, since it uses as much as digits as its factorization.

21025504813824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1728 (or 1695 counting only the distinct ones).

The product of its (nonzero) digits is 614400, while the sum is 45.

The spelling of 21025504813824 in words is "twenty-one trillion, twenty-five billion, five hundred four million, eight hundred thirteen thousand, eight hundred twenty-four".