18217939 has 8 divisors (see below), whose sum is σ = 18703872. Its totient is φ = 17734920.

The previous prime is 18217937. The next prime is 18217957. The reversal of 18217939 is 93971281.

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

It is not a de Polignac number, because 18217939 - 2¹ = 18217937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18217937) 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, 18042 + ... + 19024.

It is an arithmetic number, because the mean of its divisors is an integer number (2337984).

Almost surely, 2^18217939 is an apocalyptic number.

18217939 is a deficient number, since it is larger than the sum of its proper divisors (485933).

18217939 is an equidigital number, since it uses as much as digits as its factorization.

18217939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1457.

The product of its digits is 27216, while the sum is 40.

The square root of 18217939 is about 4268.2477669414. The cubic root of 18217939 is about 263.1276060586.

The spelling of 18217939 in words is "eighteen million, two hundred seventeen thousand, nine hundred thirty-nine".