21170189 has 4 divisors (see below), whose sum is σ = 22090656. Its totient is φ = 20249724.

The previous prime is 21170159. The next prime is 21170207. The reversal of 21170189 is 98107112.

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-21170189 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 (21170119) 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, 460199 + ... + 460244.

It is an arithmetic number, because the mean of its divisors is an integer number (5522664).

Almost surely, 2^21170189 is an apocalyptic number.

It is an amenable number.

21170189 is a deficient number, since it is larger than the sum of its proper divisors (920467).

21170189 is an equidigital number, since it uses as much as digits as its factorization.

21170189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 920466.

The product of its (nonzero) digits is 1008, while the sum is 29.

The square root of 21170189 is about 4601.1073667108. The cubic root of 21170189 is about 276.6357125738.

The spelling of 21170189 in words is "twenty-one million, one hundred seventy thousand, one hundred eighty-nine".