21528756155 has 16 divisors (see below), whose sum is σ = 26877886464. Its totient is φ = 16536169440.

The previous prime is 21528756097. The next prime is 21528756163. The reversal of 21528756155 is 55165782512.

It is a de Polignac number, because none of the positive numbers 2^k-21528756155 is a prime.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 527147 + ... + 566516.

It is an arithmetic number, because the mean of its divisors is an integer number (1679867904).

Almost surely, 2^21528756155 is an apocalyptic number.

21528756155 is a deficient number, since it is larger than the sum of its proper divisors (5349130309).

21528756155 is a wasteful number, since it uses less digits than its factorization.

21528756155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1093826.

The product of its digits is 840000, while the sum is 47.

The spelling of 21528756155 in words is "twenty-one billion, five hundred twenty-eight million, seven hundred fifty-six thousand, one hundred fifty-five".