18240390 has 80 divisors (see below), whose sum is σ = 56070432. Its totient is φ = 4167936.

The previous prime is 18240377. The next prime is 18240401. The reversal of 18240390 is 9304281.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 39 ways as a sum of consecutive naturals, for example, 4062 + ... + 7278.

Almost surely, 2^18240390 is an apocalyptic number.

18240390 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 18240390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28035216).

18240390 is an abundant number, since it is smaller than the sum of its proper divisors (37830042).

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

18240390 is a wasteful number, since it uses less digits than its factorization.

18240390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3243 (or 3234 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 18240390 is about 4270.8769591268. The cubic root of 18240390 is about 263.2356507142.

The spelling of 18240390 in words is "eighteen million, two hundred forty thousand, three hundred ninety".