21310544556 has 192 divisors, whose sum is σ = 65475916800. Its totient is φ = 5864721408.

The previous prime is 21310544509. The next prime is 21310544579. The reversal of 21310544556 is 65544501312.

21310544556 is a `hidden beast` number, since 21 + 31 + 0 + 54 + 4 + 556 = 666.

It is a super-2 number, since 2×21310544556² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21310544556.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11991540 + ... + 11993316.

It is an arithmetic number, because the mean of its divisors is an integer number (341020400).

Almost surely, 2^21310544556 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21310544556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32737958400).

21310544556 is an abundant number, since it is smaller than the sum of its proper divisors (44165372244).

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

21310544556 is a wasteful number, since it uses less digits than its factorization.

21310544556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2373 (or 2365 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

The spelling of 21310544556 in words is "twenty-one billion, three hundred ten million, five hundred forty-four thousand, five hundred fifty-six".