21323109 has 4 divisors (see below), whose sum is σ = 28430816. Its totient is φ = 14215404.

The previous prime is 21323089. The next prime is 21323129. The reversal of 21323109 is 90132312.

It is a happy number.

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 an interprime number because it is at equal distance from previous prime (21323089) and next prime (21323129).

It is not a de Polignac number, because 21323109 - 2⁵ = 21323077 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 (21323129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3553849 + ... + 3553854.

It is an arithmetic number, because the mean of its divisors is an integer number (7107704).

Almost surely, 2^21323109 is an apocalyptic number.

It is an amenable number.

21323109 is a deficient number, since it is larger than the sum of its proper divisors (7107707).

21323109 is an equidigital number, since it uses as much as digits as its factorization.

21323109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7107706.

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 21323109 is about 4617.6952043200. The cubic root of 21323109 is about 277.3001954301.

The spelling of 21323109 in words is "twenty-one million, three hundred twenty-three thousand, one hundred nine".