21833213 has 4 divisors (see below), whose sum is σ = 22078620. Its totient is φ = 21587808.

The previous prime is 21833209. The next prime is 21833237. The reversal of 21833213 is 31233812.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10252804 + 11580409 = 3202^2 + 3403^2 .

It is a cyclic number.

It is not a de Polignac number, because 21833213 - 2² = 21833209 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 (21833263) 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, 122570 + ... + 122747.

It is an arithmetic number, because the mean of its divisors is an integer number (5519655).

Almost surely, 2^21833213 is an apocalyptic number.

It is an amenable number.

21833213 is a deficient number, since it is larger than the sum of its proper divisors (245407).

21833213 is an equidigital number, since it uses as much as digits as its factorization.

21833213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245406.

The product of its digits is 864, while the sum is 23.

The square root of 21833213 is about 4672.6023798308. The cubic root of 21833213 is about 279.4940395105.

The spelling of 21833213 in words is "twenty-one million, eight hundred thirty-three thousand, two hundred thirteen".