665506 has 8 divisors (see below), whose sum is σ = 1002780. Its totient is φ = 331248.

The previous prime is 665503. The next prime is 665507. The reversal of 665506 is 605566.

It can be written as a sum of positive squares in 2 ways, for example, as 654481 + 11025 = 809^2 + 105^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (665501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81 + ... + 1156.

2⁶⁶⁵⁵⁰⁶ is an apocalyptic number.

665506 is a deficient number, since it is larger than the sum of its proper divisors (337274).

665506 is a wasteful number, since it uses less digits than its factorization.

665506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1508.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 665506 is about 815.7855110260. The cubic root of 665506 is about 87.3073202378.

The spelling of 665506 in words is "six hundred sixty-five thousand, five hundred six".