21555453264 has 20 divisors (see below), whose sum is σ = 55684921056. Its totient is φ = 7185151072.

The previous prime is 21555453253. The next prime is 21555453289. The reversal of 21555453264 is 46235455512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224535924 + ... + 224536019.

Almost surely, 2^21555453264 is an apocalyptic number.

21555453264 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21555453264 is an abundant number, since it is smaller than the sum of its proper divisors (34129467792).

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

21555453264 is a wasteful number, since it uses less digits than its factorization.

21555453264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449071954 (or 449071948 counting only the distinct ones).

The product of its digits is 720000, while the sum is 42.

The spelling of 21555453264 in words is "twenty-one billion, five hundred fifty-five million, four hundred fifty-three thousand, two hundred sixty-four".