21917423585 has 4 divisors (see below), whose sum is σ = 26300908308. Its totient is φ = 17533938864.

The previous prime is 21917423573. The next prime is 21917423599. The reversal of 21917423585 is 58532471912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3346275409 + 18571148176 = 57847^2 + 136276^2 .

It is a cyclic number.

It is not a de Polignac number, because 21917423585 - 2⁸ = 21917423329 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2191742354 + ... + 2191742363.

It is an arithmetic number, because the mean of its divisors is an integer number (6575227077).

Almost surely, 2^21917423585 is an apocalyptic number.

It is an amenable number.

21917423585 is a deficient number, since it is larger than the sum of its proper divisors (4383484723).

21917423585 is an equidigital number, since it uses as much as digits as its factorization.

21917423585 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4383484722.

The product of its digits is 604800, while the sum is 47.

The spelling of 21917423585 in words is "twenty-one billion, nine hundred seventeen million, four hundred twenty-three thousand, five hundred eighty-five".