18981090 has 24 divisors (see below), whose sum is σ = 49351068. Its totient is φ = 5061600.

The previous prime is 18981089. The next prime is 18981107. The reversal of 18981090 is 9018981.

It can be written as a sum of positive squares in 2 ways, for example, as 18896409 + 84681 = 4347^2 + 291^2 .

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 105361 + ... + 105540.

Almost surely, 2^18981090 is an apocalyptic number.

18981090 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18981090 is an abundant number, since it is smaller than the sum of its proper divisors (30369978).

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

18981090 is a wasteful number, since it uses less digits than its factorization.

18981090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210914 (or 210911 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 18981090 is about 4356.7292777954. The cubic root of 18981090 is about 266.7516100922.

The spelling of 18981090 in words is "eighteen million, nine hundred eighty-one thousand, ninety".