21239185 has 16 divisors (see below), whose sum is σ = 28703232. Its totient is φ = 14947200.

The previous prime is 21239177. The next prime is 21239191. The reversal of 21239185 is 58193212.

It is not a de Polignac number, because 21239185 - 2³ = 21239177 is a prime.

It is a super-2 number, since 2×21239185² = 902205958928450, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4524 + ... + 7933.

It is an arithmetic number, because the mean of its divisors is an integer number (1793952).

Almost surely, 2^21239185 is an apocalyptic number.

It is an amenable number.

21239185 is a deficient number, since it is larger than the sum of its proper divisors (7464047).

21239185 is a wasteful number, since it uses less digits than its factorization.

21239185 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12504.

The product of its digits is 4320, while the sum is 31.

The square root of 21239185 is about 4608.5990279043. The cubic root of 21239185 is about 276.9359155274.

The spelling of 21239185 in words is "twenty-one million, two hundred thirty-nine thousand, one hundred eighty-five".