18318998 has 4 divisors (see below), whose sum is σ = 27478500. Its totient is φ = 9159498.

The previous prime is 18318991. The next prime is 18319003. The reversal of 18318998 is 89981381.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 89981381 = 7 ⋅12854483.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18318991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4579748 + ... + 4579751.

It is an arithmetic number, because the mean of its divisors is an integer number (6869625).

Almost surely, 2^18318998 is an apocalyptic number.

18318998 is a deficient number, since it is larger than the sum of its proper divisors (9159502).

18318998 is an equidigital number, since it uses as much as digits as its factorization.

18318998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9159501.

The product of its digits is 124416, while the sum is 47.

The square root of 18318998 is about 4280.0698592430. The cubic root of 18318998 is about 263.6132518132.

The spelling of 18318998 in words is "eighteen million, three hundred eighteen thousand, nine hundred ninety-eight".