18517998 has 16 divisors (see below), whose sum is σ = 39214800. Its totient is φ = 5809536.

The previous prime is 18517991. The next prime is 18517999. The reversal of 18517998 is 89971581.

18517998 is nontrivially palindromic in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18517991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90673 + ... + 90876.

It is an arithmetic number, because the mean of its divisors is an integer number (2450925).

Almost surely, 2^18517998 is an apocalyptic number.

18517998 is an abundant number, since it is smaller than the sum of its proper divisors (20696802).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18517998 is a wasteful number, since it uses less digits than its factorization.

18517998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181571.

The product of its digits is 181440, while the sum is 48.

The square root of 18517998 is about 4303.2543499078. The cubic root of 18517998 is about 264.5643631565.

The spelling of 18517998 in words is "eighteen million, five hundred seventeen thousand, nine hundred ninety-eight".