21105521057156 has 24 divisors (see below), whose sum is σ = 37563567145440. Its totient is φ = 10373100864192.

The previous prime is 21105521057143. The next prime is 21105521057189. The reversal of 21105521057156 is 65175012550112.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 370121 + ... + 6507536.

It is an arithmetic number, because the mean of its divisors is an integer number (1565148631060).

Almost surely, 2^{21105521057156} is an apocalyptic number.

It is an amenable number.

21105521057156 is a deficient number, since it is larger than the sum of its proper divisors (16458046088284).

21105521057156 is a wasteful number, since it uses less digits than its factorization.

21105521057156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6890723 (or 6890721 counting only the distinct ones).

The product of its (nonzero) digits is 105000, while the sum is 41.

The spelling of 21105521057156 in words is "twenty-one trillion, one hundred five billion, five hundred twenty-one million, fifty-seven thousand, one hundred fifty-six".