21694865865 has 16 divisors (see below), whose sum is σ = 34716825600. Its totient is φ = 11568915072.

The previous prime is 21694865849. The next prime is 21694865887. The reversal of 21694865865 is 56856849612.

It is not a de Polignac number, because 21694865865 - 2⁴ = 21694865849 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21694865799 and 21694865808.

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, 5496 + ... + 208374.

It is an arithmetic number, because the mean of its divisors is an integer number (2169801600).

Almost surely, 2^21694865865 is an apocalyptic number.

It is an amenable number.

21694865865 is a deficient number, since it is larger than the sum of its proper divisors (13021959735).

21694865865 is a wasteful number, since it uses less digits than its factorization.

21694865865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210016.

The product of its digits is 24883200, while the sum is 60.

The spelling of 21694865865 in words is "twenty-one billion, six hundred ninety-four million, eight hundred sixty-five thousand, eight hundred sixty-five".