18213239 has 8 divisors (see below), whose sum is σ = 21037968. Its totient is φ = 15583360.

The previous prime is 18213233. The next prime is 18213253. The reversal of 18213239 is 93231281.

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

It is a cyclic number.

It is not a de Polignac number, because 18213239 - 2²⁴ = 1436023 is a prime.

It is a super-2 number, since 2×18213239² = 663444149742242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18213233) 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, 48512 + ... + 48885.

It is an arithmetic number, because the mean of its divisors is an integer number (2629746).

Almost surely, 2^18213239 is an apocalyptic number.

18213239 is a deficient number, since it is larger than the sum of its proper divisors (2824729).

18213239 is a wasteful number, since it uses less digits than its factorization.

18213239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97425.

The product of its digits is 2592, while the sum is 29.

The square root of 18213239 is about 4267.6971542039. The cubic root of 18213239 is about 263.1049762372.

The spelling of 18213239 in words is "eighteen million, two hundred thirteen thousand, two hundred thirty-nine".