18994809 has 4 divisors (see below), whose sum is σ = 25326416. Its totient is φ = 12663204.

The previous prime is 18994793. The next prime is 18994817. The reversal of 18994809 is 90849981.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 18994809 - 2⁴ = 18994793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18994309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3165799 + ... + 3165804.

It is an arithmetic number, because the mean of its divisors is an integer number (6331604).

Almost surely, 2^18994809 is an apocalyptic number.

It is an amenable number.

18994809 is a deficient number, since it is larger than the sum of its proper divisors (6331607).

18994809 is an equidigital number, since it uses as much as digits as its factorization.

18994809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6331606.

The product of its (nonzero) digits is 186624, while the sum is 48.

The square root of 18994809 is about 4358.3034543272. The cubic root of 18994809 is about 266.8158614781.

The spelling of 18994809 in words is "eighteen million, nine hundred ninety-four thousand, eight hundred nine".