18381690 has 48 divisors (see below), whose sum is σ = 48117888. Its totient is φ = 4868448.

The previous prime is 18381677. The next prime is 18381691. The reversal of 18381690 is 9618381.

It is a super-2 number, since 2×18381690² = 675773054512200, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (18381691) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14419 + ... + 15641.

It is an arithmetic number, because the mean of its divisors is an integer number (1002456).

Almost surely, 2^18381690 is an apocalyptic number.

18381690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18381690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24058944).

18381690 is an abundant number, since it is smaller than the sum of its proper divisors (29736198).

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

18381690 is a wasteful number, since it uses less digits than its factorization.

18381690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1403 (or 1400 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 18381690 is about 4287.3873163035. The cubic root of 18381690 is about 263.9136253246.

The spelling of 18381690 in words is "eighteen million, three hundred eighty-one thousand, six hundred ninety".