21030055915 has 24 divisors (see below), whose sum is σ = 28193601744. Its totient is φ = 15043828800.

The previous prime is 21030055903. The next prime is 21030055933. The reversal of 21030055915 is 51955003012.

It is not a de Polignac number, because 21030055915 - 2⁵ = 21030055883 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 248017 + ... + 321826.

It is an arithmetic number, because the mean of its divisors is an integer number (1174733406).

Almost surely, 2^21030055915 is an apocalyptic number.

21030055915 is a deficient number, since it is larger than the sum of its proper divisors (7163545829).

21030055915 is a wasteful number, since it uses less digits than its factorization.

21030055915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 569931 (or 569920 counting only the distinct ones).

The product of its (nonzero) digits is 6750, while the sum is 31.

Adding to 21030055915 its reverse (51955003012), we get a palindrome (72985058927).

The spelling of 21030055915 in words is "twenty-one billion, thirty million, fifty-five thousand, nine hundred fifteen".