665983 has 2 divisors, whose sum is σ = 665984. Its totient is φ = 665982.

The previous prime is 665981. The next prime is 665993. The reversal of 665983 is 389566.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 665983 - 2¹ = 665981 is a prime.

Together with 665981, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332991 + 332992.

It is an arithmetic number, because the mean of its divisors is an integer number (332992).

2⁶⁶⁵⁹⁸³ is an apocalyptic number.

665983 is a deficient number, since it is larger than the sum of its proper divisors (1).

665983 is an equidigital number, since it uses as much as digits as its factorization.

665983 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 37.

The square root of 665983 is about 816.0778149172. The cubic root of 665983 is about 87.3281743678.

The spelling of 665983 in words is "six hundred sixty-five thousand, nine hundred eighty-three".