18990390 has 16 divisors (see below), whose sum is σ = 45577008. Its totient is φ = 5064096.

The previous prime is 18990379. The next prime is 18990427. The reversal of 18990390 is 9309981.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 316477 + ... + 316536.

It is an arithmetic number, because the mean of its divisors is an integer number (2848563).

Almost surely, 2^18990390 is an apocalyptic number.

18990390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18990390 is an abundant number, since it is smaller than the sum of its proper divisors (26586618).

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

18990390 is a wasteful number, since it uses less digits than its factorization.

18990390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 633023.

The product of its (nonzero) digits is 17496, while the sum is 39.

The square root of 18990390 is about 4357.7964615158. The cubic root of 18990390 is about 266.7951689697.

The spelling of 18990390 in words is "eighteen million, nine hundred ninety thousand, three hundred ninety".