18400990 has 16 divisors (see below), whose sum is σ = 33892848. Its totient is φ = 7189056.

The previous prime is 18400981. The next prime is 18401023. The reversal of 18400990 is 9900481.

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 7 ways as a sum of consecutive naturals, for example, 20967 + ... + 21826.

It is an arithmetic number, because the mean of its divisors is an integer number (2118303).

Almost surely, 2^18400990 is an apocalyptic number.

18400990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18400990 is a deficient number, since it is larger than the sum of its proper divisors (15491858).

18400990 is a wasteful number, since it uses less digits than its factorization.

18400990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42843.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 18400990 is about 4289.6375138233. The cubic root of 18400990 is about 264.0059590788.

The spelling of 18400990 in words is "eighteen million, four hundred thousand, nine hundred ninety".