21165233 has 4 divisors (see below), whose sum is σ = 21481200. Its totient is φ = 20849268.

The previous prime is 21165229. The next prime is 21165241. The reversal of 21165233 is 33256112.

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 21165233 - 2² = 21165229 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21165199 and 21165208.

It is not an unprimeable number, because it can be changed into a prime (21165533) 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, 157883 + ... + 158016.

It is an arithmetic number, because the mean of its divisors is an integer number (5370300).

Almost surely, 2^21165233 is an apocalyptic number.

It is an amenable number.

21165233 is a deficient number, since it is larger than the sum of its proper divisors (315967).

21165233 is an equidigital number, since it uses as much as digits as its factorization.

21165233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315966.

The product of its digits is 1080, while the sum is 23.

The square root of 21165233 is about 4600.5687691850. The cubic root of 21165233 is about 276.6141238263.

The spelling of 21165233 in words is "twenty-one million, one hundred sixty-five thousand, two hundred thirty-three".