21155165220512 has 48 divisors (see below), whose sum is σ = 45026196294240. Its totient is φ = 9750033462528.

The previous prime is 21155165220509. The next prime is 21155165220533. The reversal of 21155165220512 is 21502256155112.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 470175878 + ... + 470220869.

It is an arithmetic number, because the mean of its divisors is an integer number (938045756130).

Almost surely, 2^{21155165220512} is an apocalyptic number.

It is an amenable number.

21155165220512 is an abundant number, since it is smaller than the sum of its proper divisors (23871031073728).

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

21155165220512 is a wasteful number, since it uses less digits than its factorization.

21155165220512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 940396813 (or 940396805 counting only the distinct ones).

The product of its (nonzero) digits is 60000, while the sum is 38.

The spelling of 21155165220512 in words is "twenty-one trillion, one hundred fifty-five billion, one hundred sixty-five million, two hundred twenty thousand, five hundred twelve".