665040 has 80 divisors (see below), whose sum is σ = 2196288. Its totient is φ = 165888.

The previous prime is 665039. The next prime is 665047. The reversal of 665040 is 40566.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 664998 and 665016.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 665040.

It is not an unprimeable number, because it can be changed into a prime (665047) 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, 3999 + ... + 4161.

2⁶⁶⁵⁰⁴⁰ is an apocalyptic number.

665040 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is a pronic number, being equal to 815×816.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1098144).

665040 is an abundant number, since it is smaller than the sum of its proper divisors (1531248).

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

665040 is a wasteful number, since it uses less digits than its factorization.

665040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196 (or 190 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 665040 is about 815.4998467198. The cubic root of 665040 is about 87.2869373957.

The spelling of 665040 in words is "six hundred sixty-five thousand, forty".