18319840 has 96 divisors (see below), whose sum is σ = 53996544. Its totient is φ = 5706240.

The previous prime is 18319837. The next prime is 18319901. The reversal of 18319840 is 4891381.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 18319796 and 18319805.

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 15 ways as a sum of consecutive naturals, for example, 11577 + ... + 13063.

It is an arithmetic number, because the mean of its divisors is an integer number (562464).

Almost surely, 2^18319840 is an apocalyptic number.

18319840 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 18319840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26998272).

18319840 is an abundant number, since it is smaller than the sum of its proper divisors (35676704).

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

18319840 is a wasteful number, since it uses less digits than its factorization.

18319840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1520 (or 1512 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 18319840 is about 4280.1682209932. The cubic root of 18319840 is about 263.6172905886.

The spelling of 18319840 in words is "eighteen million, three hundred nineteen thousand, eight hundred forty".