665394 has 8 divisors (see below), whose sum is σ = 1330800. Its totient is φ = 221796.

The previous prime is 665387. The next prime is 665419. The reversal of 665394 is 493566.

It is a happy number.

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

665394 is an admirable number.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a plaindrome in base 9.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55444 + ... + 55455.

It is an arithmetic number, because the mean of its divisors is an integer number (166350).

2⁶⁶⁵³⁹⁴ is an apocalyptic number.

665394 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

665394 is a wasteful number, since it uses less digits than its factorization.

665394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110904.

The product of its digits is 19440, while the sum is 33.

The square root of 665394 is about 815.7168626429. The cubic root of 665394 is about 87.3024222261.

It can be divided in two parts, 66 and 5394, that added together give a triangular number (5460 = T₁₀₄).

The spelling of 665394 in words is "six hundred sixty-five thousand, three hundred ninety-four".