21099323 has 4 divisors (see below), whose sum is σ = 24113520. Its totient is φ = 18085128.

The previous prime is 21099301. The next prime is 21099371. The reversal of 21099323 is 32399012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21099323 - 2¹² = 21095227 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21099383) 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, 1507088 + ... + 1507101.

It is an arithmetic number, because the mean of its divisors is an integer number (6028380).

Almost surely, 2^21099323 is an apocalyptic number.

21099323 is a deficient number, since it is larger than the sum of its proper divisors (3014197).

21099323 is an equidigital number, since it uses as much as digits as its factorization.

21099323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3014196.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 21099323 is about 4593.3999390430. The cubic root of 21099323 is about 276.3266934199.

The spelling of 21099323 in words is "twenty-one million, ninety-nine thousand, three hundred twenty-three".