21554871138 has 48 divisors (see below), whose sum is σ = 49214443200. Its totient is φ = 6799295520.

The previous prime is 21554871133. The next prime is 21554871181. The reversal of 21554871138 is 83117845512.

21554871138 is a `hidden beast` number, since 2 + 1 + 5 + 548 + 71 + 1 + 38 = 666.

It is a super-2 number, since 2×21554871138² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21554871093 and 21554871102.

It is not an unprimeable number, because it can be changed into a prime (21554871133) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 280008 + ... + 348588.

It is an arithmetic number, because the mean of its divisors is an integer number (1025300900).

Almost surely, 2^21554871138 is an apocalyptic number.

21554871138 is an abundant number, since it is smaller than the sum of its proper divisors (27659572062).

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

21554871138 is a wasteful number, since it uses less digits than its factorization.

21554871138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69527 (or 69524 counting only the distinct ones).

The product of its digits is 268800, while the sum is 45.

The spelling of 21554871138 in words is "twenty-one billion, five hundred fifty-four million, eight hundred seventy-one thousand, one hundred thirty-eight".