21115456056 has 64 divisors (see below), whose sum is σ = 58666010400. Its totient is φ = 7037049600.

The previous prime is 21115456049. The next prime is 21115456057. The reversal of 21115456056 is 65065451112.

21115456056 is a `hidden beast` number, since 2 + 1 + 1 + 1 + 5 + 45 + 605 + 6 = 666.

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 21115456056.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115456057) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1869466 + ... + 1880726.

Almost surely, 2^21115456056 is an apocalyptic number.

It is an amenable number.

21115456056 is an abundant number, since it is smaller than the sum of its proper divisors (37550554344).

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

21115456056 is a wasteful number, since it uses less digits than its factorization.

21115456056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19957 (or 19947 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

The spelling of 21115456056 in words is "twenty-one billion, one hundred fifteen million, four hundred fifty-six thousand, fifty-six".