18165940 has 48 divisors (see below), whose sum is σ = 41524560. Its totient is φ = 6635520.

The previous prime is 18165913. The next prime is 18165947. The reversal of 18165940 is 4956181.

It can be written as a sum of positive squares in 8 ways, for example, as 86436 + 18079504 = 294^2 + 4252^2 .

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 18165896 and 18165905.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18165947) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28020 + ... + 28660.

It is an arithmetic number, because the mean of its divisors is an integer number (865095).

Almost surely, 2^18165940 is an apocalyptic number.

18165940 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 18165940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20762280).

18165940 is an abundant number, since it is smaller than the sum of its proper divisors (23358620).

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

18165940 is a wasteful number, since it uses less digits than its factorization.

18165940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 772 (or 770 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 34.

The square root of 18165940 is about 4262.1520385833. The cubic root of 18165940 is about 262.8770213497.

The spelling of 18165940 in words is "eighteen million, one hundred sixty-five thousand, nine hundred forty".