665913 has 8 divisors (see below), whose sum is σ = 901408. Its totient is φ = 437184.

The previous prime is 665897. The next prime is 665921. The reversal of 665913 is 319566.

It is a happy number.

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

It is not a de Polignac number, because 665913 - 2⁴ = 665897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1456 + ... + 1857.

It is an arithmetic number, because the mean of its divisors is an integer number (112676).

2⁶⁶⁵⁹¹³ is an apocalyptic number.

It is an amenable number.

665913 is a deficient number, since it is larger than the sum of its proper divisors (235495).

665913 is a wasteful number, since it uses less digits than its factorization.

665913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3383.

The product of its digits is 4860, while the sum is 30.

The square root of 665913 is about 816.0349257232. The cubic root of 665913 is about 87.3251146369.

The spelling of 665913 in words is "six hundred sixty-five thousand, nine hundred thirteen".