18991022 has 8 divisors (see below), whose sum is σ = 28548936. Its totient is φ = 9474712.

The previous prime is 18991019. The next prime is 18991033. The reversal of 18991022 is 22019981.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 18991022.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 9233 + ... + 11100.

It is an arithmetic number, because the mean of its divisors is an integer number (3568617).

Almost surely, 2^18991022 is an apocalyptic number.

18991022 is a deficient number, since it is larger than the sum of its proper divisors (9557914).

18991022 is a wasteful number, since it uses less digits than its factorization.

18991022 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20802.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 18991022 is about 4357.8689746251. The cubic root of 18991022 is about 266.7981285837.

The spelling of 18991022 in words is "eighteen million, nine hundred ninety-one thousand, twenty-two".