21551552403504 has 40 divisors (see below), whose sum is σ = 55676352495792. Its totient is φ = 7183656119040.

The previous prime is 21551552403503. The next prime is 21551552403517. The reversal of 21551552403504 is 40530425515512.

It is a happy number.

It is a super-2 number, since 2×21551552403504² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21551552403503) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4288687 + ... + 7841934.

Almost surely, 2^{21551552403504} is an apocalyptic number.

21551552403504 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21551552403504 is an abundant number, since it is smaller than the sum of its proper divisors (34124800092288).

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

21551552403504 is a wasteful number, since it uses less digits than its factorization.

21551552403504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12167645 (or 12167639 counting only the distinct ones).

The product of its (nonzero) digits is 600000, while the sum is 42.

The spelling of 21551552403504 in words is "twenty-one trillion, five hundred fifty-one billion, five hundred fifty-two million, four hundred three thousand, five hundred four".