21155555163312 has 120 divisors (see below), whose sum is σ = 59778023872320. Its totient is φ = 6983781168000.

The previous prime is 21155555163287. The next prime is 21155555163329. The reversal of 21155555163312 is 21336155555112.

21155555163312 is a `hidden beast` number, since 2 + 1 + 1 + 5 + 5 + 5 + 5 + 5 + 1 + 633 + 1 + 2 = 666.

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, 49880239 + ... + 50302577.

It is an arithmetic number, because the mean of its divisors is an integer number (498150198936).

Almost surely, 2^{21155555163312} 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 21155555163312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29889011936160).

21155555163312 is an abundant number, since it is smaller than the sum of its proper divisors (38622468709008).

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

21155555163312 is a wasteful number, since it uses less digits than its factorization.

21155555163312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 425711 (or 425702 counting only the distinct ones).

The product of its digits is 675000, while the sum is 45.

The spelling of 21155555163312 in words is "twenty-one trillion, one hundred fifty-five billion, five hundred fifty-five million, one hundred sixty-three thousand, three hundred twelve".