21154510222056 has 96 divisors (see below), whose sum is σ = 57897020530440. Its totient is φ = 6977252081664.

The previous prime is 21154510222031. The next prime is 21154510222061. The reversal of 21154510222056 is 65022201545112.

21154510222056 is a `hidden beast` number, since 2 + 1 + 1 + 54 + 510 + 22 + 20 + 56 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 9414526256100 + 11739983965956 = 3068310^2 + 3426366^2 .

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 21154510222056.

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, 31211440 + ... + 31882016.

Almost surely, 2^{21154510222056} 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 21154510222056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28948510265220).

21154510222056 is an abundant number, since it is smaller than the sum of its proper divisors (36742510308384).

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

21154510222056 is a wasteful number, since it uses less digits than its factorization.

21154510222056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 675203 (or 675196 counting only the distinct ones).

The product of its (nonzero) digits is 48000, while the sum is 36.

Adding to 21154510222056 its reverse (65022201545112), we get a palindrome (86176711767168).

The spelling of 21154510222056 in words is "twenty-one trillion, one hundred fifty-four billion, five hundred ten million, two hundred twenty-two thousand, fifty-six".