21938185 has 8 divisors (see below), whose sum is σ = 26368776. Its totient is φ = 17521920.

The previous prime is 21938183. The next prime is 21938197. The reversal of 21938185 is 58183912.

It can be written as a sum of positive squares in 4 ways, for example, as 14653584 + 7284601 = 3828^2 + 2699^2 .

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

It is not a de Polignac number, because 21938185 - 2¹ = 21938183 is a prime.

It is a super-2 number, since 2×21938185² = 962567922188450, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21938183) 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, 145 + ... + 6625.

It is an arithmetic number, because the mean of its divisors is an integer number (3296097).

Almost surely, 2^21938185 is an apocalyptic number.

It is an amenable number.

21938185 is a deficient number, since it is larger than the sum of its proper divisors (4430591).

21938185 is an equidigital number, since it uses as much as digits as its factorization.

21938185 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7163.

The product of its digits is 17280, while the sum is 37.

The square root of 21938185 is about 4683.8216234182. The cubic root of 21938185 is about 279.9412504291.

The spelling of 21938185 in words is "twenty-one million, nine hundred thirty-eight thousand, one hundred eighty-five".