21554871156 has 72 divisors (see below), whose sum is σ = 67059609344. Its totient is φ = 5684800320.

The previous prime is 21554871133. The next prime is 21554871181. The reversal of 21554871156 is 65117845512.

21554871156 is a `hidden beast` number, since 2 + 1 + 55 + 487 + 115 + 6 = 666.

It is a super-2 number, since 2×21554871156² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3286540 + ... + 3293091.

Almost surely, 2^21554871156 is an apocalyptic number.

21554871156 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21554871156 is an abundant number, since it is smaller than the sum of its proper divisors (45504738188).

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

21554871156 is a wasteful number, since it uses less digits than its factorization.

21554871156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6579661 (or 6579656 counting only the distinct ones).

The product of its digits is 336000, while the sum is 45.

The spelling of 21554871156 in words is "twenty-one billion, five hundred fifty-four million, eight hundred seventy-one thousand, one hundred fifty-six".