18987290 has 32 divisors (see below), whose sum is σ = 40120704. Its totient is φ = 6333120.

The previous prime is 18987263. The next prime is 18987299. The reversal of 18987290 is 9278981.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18987299) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 1076 + ... + 6255.

It is an arithmetic number, because the mean of its divisors is an integer number (1253772).

Almost surely, 2^18987290 is an apocalyptic number.

18987290 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18987290 is an abundant number, since it is smaller than the sum of its proper divisors (21133414).

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

18987290 is a wasteful number, since it uses less digits than its factorization.

18987290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7382.

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 18987290 is about 4357.4407626496. The cubic root of 18987290 is about 266.7806509243.

The spelling of 18987290 in words is "eighteen million, nine hundred eighty-seven thousand, two hundred ninety".