21055531105515 has 32 divisors (see below), whose sum is σ = 33887785890816. Its totient is φ = 11163498168960.

The previous prime is 21055531105463. The next prime is 21055531105523. The reversal of 21055531105515 is 51550113555012.

It is a happy number.

It is not a de Polignac number, because 21055531105515 - 2⁴³ = 12259438083307 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4310239 + ... + 7790328.

It is an arithmetic number, because the mean of its divisors is an integer number (1058993309088).

Almost surely, 2^{21055531105515} is an apocalyptic number.

21055531105515 is a deficient number, since it is larger than the sum of its proper divisors (12832254785301).

21055531105515 is a wasteful number, since it uses less digits than its factorization.

21055531105515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12101259.

The product of its (nonzero) digits is 93750, while the sum is 39.

The spelling of 21055531105515 in words is "twenty-one trillion, fifty-five billion, five hundred thirty-one million, one hundred five thousand, five hundred fifteen".