665617 has 2 divisors, whose sum is σ = 665618. Its totient is φ = 665616.

The previous prime is 665603. The next prime is 665629. The reversal of 665617 is 716566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 404496 + 261121 = 636^2 + 511^2 .

It is a cyclic number.

It is not a de Polignac number, because 665617 - 2¹¹ = 663569 is a prime.

It is a Chen prime.

665617 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (665677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332808 + 332809.

It is an arithmetic number, because the mean of its divisors is an integer number (332809).

2⁶⁶⁵⁶¹⁷ is an apocalyptic number.

It is an amenable number.

665617 is a deficient number, since it is larger than the sum of its proper divisors (1).

665617 is an equidigital number, since it uses as much as digits as its factorization.

665617 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7560, while the sum is 31.

The square root of 665617 is about 815.8535407780. The cubic root of 665617 is about 87.3121739751.

The spelling of 665617 in words is "six hundred sixty-five thousand, six hundred seventeen".