165440 has 56 divisors (see below), whose sum is σ = 438912. Its totient is φ = 58880.

The previous prime is 165437. The next prime is 165443. The reversal of 165440 is 44561.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (165437) and next prime (165443).

It is a hoax number, since the sum of its digits (20) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (165443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3497 + ... + 3543.

2¹⁶⁵⁴⁴⁰ is an apocalyptic number.

165440 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 165440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (219456).

165440 is an abundant number, since it is smaller than the sum of its proper divisors (273472).

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

165440 is a wasteful number, since it uses less digits than its factorization.

165440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75 (or 65 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 165440 is about 406.7431622044. The cubic root of 165440 is about 54.8967760877.

The spelling of 165440 in words is "one hundred sixty-five thousand, four hundred forty".