21658217189 has 4 divisors (see below), whose sum is σ = 24752248224. Its totient is φ = 18564186156.

The previous prime is 21658217153. The next prime is 21658217197. The reversal of 21658217189 is 98171285612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21658217189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21658217129) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1547015507 + ... + 1547015520.

It is an arithmetic number, because the mean of its divisors is an integer number (6188062056).

Almost surely, 2^21658217189 is an apocalyptic number.

It is an amenable number.

21658217189 is a deficient number, since it is larger than the sum of its proper divisors (3094031035).

21658217189 is an equidigital number, since it uses as much as digits as its factorization.

21658217189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3094031034.

The product of its digits is 483840, while the sum is 50.

The spelling of 21658217189 in words is "twenty-one billion, six hundred fifty-eight million, two hundred seventeen thousand, one hundred eighty-nine".