665600 has 72 divisors (see below), whose sum is σ = 1777230. Its totient is φ = 245760.

The previous prime is 665591. The next prime is 665603. The reversal of 665600 is 6566.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 369664 + 295936 = 608^2 + 544^2 .

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (665603) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 51194 + ... + 51206.

2⁶⁶⁵⁶⁰⁰ 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 665600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (888615).

665600 is an abundant number, since it is smaller than the sum of its proper divisors (1111630).

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

665600 is a wasteful number, since it uses less digits than its factorization.

665600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45 (or 20 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 23.

The square root of 665600 is about 815.8431221748. The cubic root of 665600 is about 87.3114306449.

The spelling of 665600 in words is "six hundred sixty-five thousand, six hundred".