21320233 has 4 divisors (see below), whose sum is σ = 23258448. Its totient is φ = 19382020.

The previous prime is 21320213. The next prime is 21320239. The reversal of 21320233 is 33202312.

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 not a de Polignac number, because 21320233 - 2²¹ = 19223081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21320239) 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, 969091 + ... + 969112.

It is an arithmetic number, because the mean of its divisors is an integer number (5814612).

Almost surely, 2^21320233 is an apocalyptic number.

It is an amenable number.

21320233 is a deficient number, since it is larger than the sum of its proper divisors (1938215).

21320233 is a wasteful number, since it uses less digits than its factorization.

21320233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1938214.

The product of its (nonzero) digits is 216, while the sum is 16.

The square root of 21320233 is about 4617.3837830529. The cubic root of 21320233 is about 277.2877277170.

Adding to 21320233 its reverse (33202312), we get a palindrome (54522545).

The spelling of 21320233 in words is "twenty-one million, three hundred twenty thousand, two hundred thirty-three".