21217565107 has 16 divisors (see below), whose sum is σ = 22592908800. Its totient is φ = 19868919840.

The previous prime is 21217565099. The next prime is 21217565111. The reversal of 21217565107 is 70156571212.

It is a cyclic number.

It is not a de Polignac number, because 21217565107 - 2³ = 21217565099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21217565137) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 925894 + ... + 948532.

It is an arithmetic number, because the mean of its divisors is an integer number (1412056800).

Almost surely, 2^21217565107 is an apocalyptic number.

21217565107 is a deficient number, since it is larger than the sum of its proper divisors (1375343693).

21217565107 is a wasteful number, since it uses less digits than its factorization.

21217565107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23226.

The product of its (nonzero) digits is 29400, while the sum is 37.

The spelling of 21217565107 in words is "twenty-one billion, two hundred seventeen million, five hundred sixty-five thousand, one hundred seven".