665290 has 8 divisors (see below), whose sum is σ = 1197540. Its totient is φ = 266112.

The previous prime is 665279. The next prime is 665293. The reversal of 665290 is 92566.

It can be written as a sum of positive squares in 2 ways, for example, as 657721 + 7569 = 811^2 + 87^2 .

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

It is a super-2 number, since 2×665290² = 885221568200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (665293) 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, 33255 + ... + 33274.

2⁶⁶⁵²⁹⁰ is an apocalyptic number.

665290 is a deficient number, since it is larger than the sum of its proper divisors (532250).

665290 is a wasteful number, since it uses less digits than its factorization.

665290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66536.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 665290 is about 815.6531125423. The cubic root of 665290 is about 87.2978735803.

It can be divided in two parts, 66 and 5290, that added together give a triangular number (5356 = T₁₀₃).

The spelling of 665290 in words is "six hundred sixty-five thousand, two hundred ninety".