21189323 has 2 divisors, whose sum is σ = 21189324. Its totient is φ = 21189322.

The previous prime is 21189307. The next prime is 21189331. The reversal of 21189323 is 32398112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21189323 - 2⁴ = 21189307 is a prime.

It is not a weakly prime, because it can be changed into another prime (21389323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10594661 + 10594662.

It is an arithmetic number, because the mean of its divisors is an integer number (10594662).

Almost surely, 2^21189323 is an apocalyptic number.

21189323 is a deficient number, since it is larger than the sum of its proper divisors (1).

21189323 is an equidigital number, since it uses as much as digits as its factorization.

21189323 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 29.

The square root of 21189323 is about 4603.1861791590. The cubic root of 21189323 is about 276.7190302655.

It can be divided in two parts, 21189 and 323, that added together give a palindrome (21512).

The spelling of 21189323 in words is "twenty-one million, one hundred eighty-nine thousand, three hundred twenty-three".