665965 has 8 divisors (see below), whose sum is σ = 834048. Its totient is φ = 509520.

The previous prime is 665953. The next prime is 665981. The reversal of 665965 is 569566.

It is a happy number.

665965 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 665965 - 2¹⁵ = 633197 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2781 + ... + 3010.

It is an arithmetic number, because the mean of its divisors is an integer number (104256).

2⁶⁶⁵⁹⁶⁵ is an apocalyptic number.

It is an amenable number.

665965 is a deficient number, since it is larger than the sum of its proper divisors (168083).

665965 is a wasteful number, since it uses less digits than its factorization.

665965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5819.

The product of its digits is 48600, while the sum is 37.

The square root of 665965 is about 816.0667864826. The cubic root of 665965 is about 87.3273876003.

It can be divided in two parts, 6659 and 65, that added together give a square (6724 = 82²).

The spelling of 665965 in words is "six hundred sixty-five thousand, nine hundred sixty-five".