18339840 has 144 divisors (see below), whose sum is σ = 63882000. Its totient is φ = 4866048.

The previous prime is 18339829. The next prime is 18339847. The reversal of 18339840 is 4893381.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18339795 and 18339804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18339847) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 92061 + ... + 92259.

It is an arithmetic number, because the mean of its divisors is an integer number (443625).

Almost surely, 2^18339840 is an apocalyptic number.

18339840 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 18339840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31941000).

18339840 is an abundant number, since it is smaller than the sum of its proper divisors (45542160).

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

18339840 is a wasteful number, since it uses less digits than its factorization.

18339840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232 (or 209 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 18339840 is about 4282.5039404535. The cubic root of 18339840 is about 263.7131871384.

The spelling of 18339840 in words is "eighteen million, three hundred thirty-nine thousand, eight hundred forty".