21315310055 has 24 divisors (see below), whose sum is σ = 28341461808. Its totient is φ = 15374451456.

The previous prime is 21315309979. The next prime is 21315310061. The reversal of 21315310055 is 55001351312.

It is a happy number.

It is not a de Polignac number, because 21315310055 - 2¹⁰ = 21315309031 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 256982 + ... + 329651.

It is an arithmetic number, because the mean of its divisors is an integer number (1180894242).

Almost surely, 2^21315310055 is an apocalyptic number.

21315310055 is a deficient number, since it is larger than the sum of its proper divisors (7026151753).

21315310055 is a wasteful number, since it uses less digits than its factorization.

21315310055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586707 (or 586694 counting only the distinct ones).

The product of its (nonzero) digits is 2250, while the sum is 26.

Adding to 21315310055 its reverse (55001351312), we get a palindrome (76316661367).

The spelling of 21315310055 in words is "twenty-one billion, three hundred fifteen million, three hundred ten thousand, fifty-five".