18998806 has 4 divisors (see below), whose sum is σ = 28498212. Its totient is φ = 9499402.

The previous prime is 18998801. The next prime is 18998821. The reversal of 18998806 is 60889981.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 18998806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18998801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4749700 + ... + 4749703.

It is an arithmetic number, because the mean of its divisors is an integer number (7124553).

Almost surely, 2^18998806 is an apocalyptic number.

18998806 is a deficient number, since it is larger than the sum of its proper divisors (9499406).

18998806 is an equidigital number, since it uses as much as digits as its factorization.

18998806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9499405.

The product of its (nonzero) digits is 248832, while the sum is 49.

The square root of 18998806 is about 4358.7619801958. The cubic root of 18998806 is about 266.8345751559.

The spelling of 18998806 in words is "eighteen million, nine hundred ninety-eight thousand, eight hundred six".