18638340 has 96 divisors (see below), whose sum is σ = 60211200. Its totient is φ = 4219776.

The previous prime is 18638327. The next prime is 18638363. The reversal of 18638340 is 4383681.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 83469 + ... + 83691.

It is an arithmetic number, because the mean of its divisors is an integer number (627200).

Almost surely, 2^18638340 is an apocalyptic number.

18638340 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18638340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30105600).

18638340 is an abundant number, since it is smaller than the sum of its proper divisors (41572860).

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

18638340 is a wasteful number, since it uses less digits than its factorization.

18638340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 441 (or 439 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 18638340 is about 4317.2143796666. The cubic root of 18638340 is about 265.1362299437.

The spelling of 18638340 in words is "eighteen million, six hundred thirty-eight thousand, three hundred forty".