21306616635 has 16 divisors (see below), whose sum is σ = 34092688896. Its totient is φ = 11362828128.

The previous prime is 21306616627. The next prime is 21306616673. The reversal of 21306616635 is 53661660312.

It is a happy number.

It is not a de Polignac number, because 21306616635 - 2³ = 21306616627 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21306616593 and 21306616602.

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, 289252 + ... + 355358.

It is an arithmetic number, because the mean of its divisors is an integer number (2130793056).

Almost surely, 2^21306616635 is an apocalyptic number.

21306616635 is a deficient number, since it is larger than the sum of its proper divisors (12786072261).

21306616635 is a wasteful number, since it uses less digits than its factorization.

21306616635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87602.

The product of its (nonzero) digits is 116640, while the sum is 39.

The spelling of 21306616635 in words is "twenty-one billion, three hundred six million, six hundred sixteen thousand, six hundred thirty-five".