18991098 has 40 divisors (see below), whose sum is σ = 48636192. Its totient is φ = 5425704.

The previous prime is 18991081. The next prime is 18991117. The reversal of 18991098 is 89019981.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 7240 + ... + 9507.

Almost surely, 2^18991098 is an apocalyptic number.

18991098 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

18991098 is an abundant number, since it is smaller than the sum of its proper divisors (29645094).

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

18991098 is a wasteful number, since it uses less digits than its factorization.

18991098 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16768 (or 16759 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 45.

The square root of 18991098 is about 4357.8776944747. The cubic root of 18991098 is about 266.7984844823.

The spelling of 18991098 in words is "eighteen million, nine hundred ninety-one thousand, ninety-eight".