21393213 has 8 divisors (see below), whose sum is σ = 29508000. Its totient is φ = 13770288.

The previous prime is 21393187. The next prime is 21393233. The reversal of 21393213 is 31239312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21393213 - 2⁵ = 21393181 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21393233) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 122863 + ... + 123036.

It is an arithmetic number, because the mean of its divisors is an integer number (3688500).

Almost surely, 2^21393213 is an apocalyptic number.

It is an amenable number.

21393213 is a deficient number, since it is larger than the sum of its proper divisors (8114787).

21393213 is a wasteful number, since it uses less digits than its factorization.

21393213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245931.

The product of its digits is 972, while the sum is 24.

The square root of 21393213 is about 4625.2797753217. The cubic root of 21393213 is about 277.6037563475.

The spelling of 21393213 in words is "twenty-one million, three hundred ninety-three thousand, two hundred thirteen".