21917423587 has 16 divisors (see below), whose sum is σ = 23954271264. Its totient is φ = 19971328000.

The previous prime is 21917423573. The next prime is 21917423599. The reversal of 21917423587 is 78532471912.

It is not a de Polignac number, because 21917423587 - 2¹⁹ = 21916899299 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21917423587.

It is not an unprimeable number, because it can be changed into a prime (21917423527) 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, 28714 + ... + 211327.

It is an arithmetic number, because the mean of its divisors is an integer number (1497141954).

Almost surely, 2^21917423587 is an apocalyptic number.

21917423587 is a deficient number, since it is larger than the sum of its proper divisors (2036847677).

21917423587 is a wasteful number, since it uses less digits than its factorization.

21917423587 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240230.

The product of its digits is 846720, while the sum is 49.

The spelling of 21917423587 in words is "twenty-one billion, nine hundred seventeen million, four hundred twenty-three thousand, five hundred eighty-seven".