21355512115 has 32 divisors (see below), whose sum is σ = 31059141120. Its totient is φ = 13760699904.

The previous prime is 21355512089. The next prime is 21355512119. The reversal of 21355512115 is 51121555312.

It is not a de Polignac number, because 21355512115 - 2⁹ = 21355511603 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21355512119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 354676 + ... + 410494.

It is an arithmetic number, because the mean of its divisors is an integer number (970598160).

Almost surely, 2^21355512115 is an apocalyptic number.

21355512115 is a deficient number, since it is larger than the sum of its proper divisors (9703629005).

21355512115 is a wasteful number, since it uses less digits than its factorization.

21355512115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56491.

The product of its digits is 7500, while the sum is 31.

The spelling of 21355512115 in words is "twenty-one billion, three hundred fifty-five million, five hundred twelve thousand, one hundred fifteen".