665967 has 4 divisors (see below), whose sum is σ = 887960. Its totient is φ = 443976.

The previous prime is 665953. The next prime is 665981. The reversal of 665967 is 769566.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (665953) and next prime (665981).

It is not a de Polignac number, because 665967 - 2¹⁹ = 141679 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110992 + ... + 110997.

It is an arithmetic number, because the mean of its divisors is an integer number (221990).

2⁶⁶⁵⁹⁶⁷ is an apocalyptic number.

665967 is a deficient number, since it is larger than the sum of its proper divisors (221993).

665967 is a wasteful number, since it uses less digits than its factorization.

665967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221992.

The product of its digits is 68040, while the sum is 39.

The square root of 665967 is about 816.0680118716. The cubic root of 665967 is about 87.3274750196.

The spelling of 665967 in words is "six hundred sixty-five thousand, nine hundred sixty-seven".