21943189 has 4 divisors (see below), whose sum is σ = 22252320. Its totient is φ = 21634060.

The previous prime is 21943177. The next prime is 21943193. The reversal of 21943189 is 98134912.

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 not a de Polignac number, because 21943189 - 2¹¹ = 21941141 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 (21943199) 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, 154459 + ... + 154600.

It is an arithmetic number, because the mean of its divisors is an integer number (5563080).

Almost surely, 2^21943189 is an apocalyptic number.

It is an amenable number.

21943189 is a deficient number, since it is larger than the sum of its proper divisors (309131).

21943189 is an equidigital number, since it uses as much as digits as its factorization.

21943189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309130.

The product of its digits is 15552, while the sum is 37.

The square root of 21943189 is about 4684.3557721420. The cubic root of 21943189 is about 279.9625332521.

The spelling of 21943189 in words is "twenty-one million, nine hundred forty-three thousand, one hundred eighty-nine".