18381390 has 16 divisors (see below), whose sum is σ = 44115408. Its totient is φ = 4901696.

The previous prime is 18381373. The next prime is 18381397. The reversal of 18381390 is 9318381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18381397) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 306327 + ... + 306386.

It is an arithmetic number, because the mean of its divisors is an integer number (2757213).

Almost surely, 2^18381390 is an apocalyptic number.

18381390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18381390 is an abundant number, since it is smaller than the sum of its proper divisors (25734018).

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

18381390 is a wasteful number, since it uses less digits than its factorization.

18381390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 612723.

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 18381390 is about 4287.3523298185. The cubic root of 18381390 is about 263.9121895748.

The spelling of 18381390 in words is "eighteen million, three hundred eighty-one thousand, three hundred ninety".