21093213 has 4 divisors (see below), whose sum is σ = 28124288. Its totient is φ = 14062140.

The previous prime is 21093199. The next prime is 21093217. The reversal of 21093213 is 31239012.

It is a happy number.

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 not a de Polignac number, because 21093213 - 2⁸ = 21092957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21093213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21093217) 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, 3515533 + ... + 3515538.

It is an arithmetic number, because the mean of its divisors is an integer number (7031072).

Almost surely, 2^21093213 is an apocalyptic number.

It is an amenable number.

21093213 is a deficient number, since it is larger than the sum of its proper divisors (7031075).

21093213 is an equidigital number, since it uses as much as digits as its factorization.

21093213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7031074.

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 21093213 is about 4592.7348061912. The cubic root of 21093213 is about 276.3000176968.

The spelling of 21093213 in words is "twenty-one million, ninety-three thousand, two hundred thirteen".