18217998 has 24 divisors (see below), whose sum is σ = 41550600. Its totient is φ = 5752944.

The previous prime is 18217993. The next prime is 18218027. The reversal of 18217998 is 89971281.

It is a super-2 number, since 2×18217998² = 663790902256008, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18217993) 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 11 ways as a sum of consecutive naturals, for example, 26293 + ... + 26976.

It is an arithmetic number, because the mean of its divisors is an integer number (1731275).

Almost surely, 2^18217998 is an apocalyptic number.

18217998 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

18217998 is an abundant number, since it is smaller than the sum of its proper divisors (23332602).

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

18217998 is a wasteful number, since it uses less digits than its factorization.

18217998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53296 (or 53293 counting only the distinct ones).

The product of its digits is 72576, while the sum is 45.

The square root of 18217998 is about 4268.2546784371. The cubic root of 18217998 is about 263.1278901103.

The spelling of 18217998 in words is "eighteen million, two hundred seventeen thousand, nine hundred ninety-eight".