21358317 has 4 divisors (see below), whose sum is σ = 28477760. Its totient is φ = 14238876.

The previous prime is 21358303. The next prime is 21358321. The reversal of 21358317 is 71385312.

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 21358317 - 2⁷ = 21358189 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 (21358367) 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, 3559717 + ... + 3559722.

It is an arithmetic number, because the mean of its divisors is an integer number (7119440).

Almost surely, 2^21358317 is an apocalyptic number.

It is an amenable number.

21358317 is a deficient number, since it is larger than the sum of its proper divisors (7119443).

21358317 is an equidigital number, since it uses as much as digits as its factorization.

21358317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7119442.

The product of its digits is 5040, while the sum is 30.

The square root of 21358317 is about 4621.5059233977. The cubic root of 21358317 is about 277.4527344221.

The spelling of 21358317 in words is "twenty-one million, three hundred fifty-eight thousand, three hundred seventeen".