665388 has 48 divisors (see below), whose sum is σ = 1770720. Its totient is φ = 216000.

The previous prime is 665387. The next prime is 665419. The reversal of 665388 is 883566.

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

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 665388.

It is not an unprimeable number, because it can be changed into a prime (665381) 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, 6538 + ... + 6638.

It is an arithmetic number, because the mean of its divisors is an integer number (36890).

2⁶⁶⁵³⁸⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (885360).

665388 is an abundant number, since it is smaller than the sum of its proper divisors (1105332).

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

665388 is a wasteful number, since it uses less digits than its factorization.

665388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175 (or 167 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 665388 is about 815.7131848879. The cubic root of 665388 is about 87.3021598171.

The spelling of 665388 in words is "six hundred sixty-five thousand, three hundred eighty-eight".