21328223 has 16 divisors (see below), whose sum is σ = 24998400. Its totient is φ = 17820000.

The previous prime is 21328213. The next prime is 21328247. The reversal of 21328223 is 32282312.

It is a cyclic number.

It is not a de Polignac number, because 21328223 - 2¹⁰ = 21327199 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21328213) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 84848 + ... + 85098.

It is an arithmetic number, because the mean of its divisors is an integer number (1562400).

Almost surely, 2^21328223 is an apocalyptic number.

21328223 is a deficient number, since it is larger than the sum of its proper divisors (3670177).

21328223 is a wasteful number, since it uses less digits than its factorization.

21328223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518.

The product of its digits is 1152, while the sum is 23.

The square root of 21328223 is about 4618.2489105721. The cubic root of 21328223 is about 277.3223623015.

The spelling of 21328223 in words is "twenty-one million, three hundred twenty-eight thousand, two hundred twenty-three".