21596919817 has 16 divisors (see below), whose sum is σ = 24402398400. Its totient is φ = 18933445440.

The previous prime is 21596919803. The next prime is 21596919821. The reversal of 21596919817 is 71891969512.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21596919817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21596919847) 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, 223618 + ... + 305284.

It is an arithmetic number, because the mean of its divisors is an integer number (1525149900).

Almost surely, 2^21596919817 is an apocalyptic number.

It is an amenable number.

21596919817 is a deficient number, since it is larger than the sum of its proper divisors (2805478583).

21596919817 is a wasteful number, since it uses less digits than its factorization.

21596919817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82536.

The product of its digits is 2449440, while the sum is 58.

The spelling of 21596919817 in words is "twenty-one billion, five hundred ninety-six million, nine hundred nineteen thousand, eight hundred seventeen".