18994209 has 16 divisors (see below), whose sum is σ = 28012992. Its totient is φ = 11371968.

The previous prime is 18994201. The next prime is 18994273. The reversal of 18994209 is 90249981.

It is not a de Polignac number, because 18994209 - 2³ = 18994201 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18994201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5139 + ... + 8024.

It is an arithmetic number, because the mean of its divisors is an integer number (1750812).

Almost surely, 2^18994209 is an apocalyptic number.

It is an amenable number.

18994209 is a deficient number, since it is larger than the sum of its proper divisors (9018783).

18994209 is a wasteful number, since it uses less digits than its factorization.

18994209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13216.

The product of its (nonzero) digits is 46656, while the sum is 42.

The square root of 18994209 is about 4358.2346196597. The cubic root of 18994209 is about 266.8130520930.

The spelling of 18994209 in words is "eighteen million, nine hundred ninety-four thousand, two hundred nine".