18966239 has 4 divisors (see below), whose sum is σ = 19369824. Its totient is φ = 18562656.

The previous prime is 18966229. The next prime is 18966251. The reversal of 18966239 is 93266981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93266981 = 17 ⋅5486293.

It is a cyclic number.

It is not a de Polignac number, because 18966239 - 2⁴ = 18966223 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18966239.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18966229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 201722 + ... + 201815.

It is an arithmetic number, because the mean of its divisors is an integer number (4842456).

Almost surely, 2^18966239 is an apocalyptic number.

18966239 is a deficient number, since it is larger than the sum of its proper divisors (403585).

18966239 is an equidigital number, since it uses as much as digits as its factorization.

18966239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403584.

The product of its digits is 139968, while the sum is 44.

The square root of 18966239 is about 4355.0245693911. The cubic root of 18966239 is about 266.6820222060.

The spelling of 18966239 in words is "eighteen million, nine hundred sixty-six thousand, two hundred thirty-nine".