21858313 has 8 divisors (see below), whose sum is σ = 22639176. Its totient is φ = 21091200.

The previous prime is 21858301. The next prime is 21858383. The reversal of 21858313 is 31385812.

It can be written as a sum of positive squares in 4 ways, for example, as 2778889 + 19079424 = 1667^2 + 4368^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21858313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21858383) 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, 148 + ... + 6613.

It is an arithmetic number, because the mean of its divisors is an integer number (2829897).

Almost surely, 2^21858313 is an apocalyptic number.

It is an amenable number.

21858313 is a deficient number, since it is larger than the sum of its proper divisors (780863).

21858313 is an equidigital number, since it uses as much as digits as its factorization.

21858313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6875.

The product of its digits is 5760, while the sum is 31.

The square root of 21858313 is about 4675.2874777921. The cubic root of 21858313 is about 279.6011029065.

The spelling of 21858313 in words is "twenty-one million, eight hundred fifty-eight thousand, three hundred thirteen".