665217 has 12 divisors (see below), whose sum is σ = 1098240. Its totient is φ = 380088.

The previous prime is 665213. The next prime is 665221. The reversal of 665217 is 712566.

665217 is a `hidden beast` number, since 6 + 652 + 1 + 7 = 666.

It is an interprime number because it is at equal distance from previous prime (665213) and next prime (665221).

It is not a de Polignac number, because 665217 - 2² = 665213 is a prime.

It is not an unprimeable number, because it can be changed into a prime (665213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5217 + ... + 5342.

It is an arithmetic number, because the mean of its divisors is an integer number (91520).

2⁶⁶⁵²¹⁷ is an apocalyptic number.

It is an amenable number.

665217 is a deficient number, since it is larger than the sum of its proper divisors (433023).

665217 is a wasteful number, since it uses less digits than its factorization.

665217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10572 (or 10569 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 665217 is about 815.6083618993. The cubic root of 665217 is about 87.2946804976.

The spelling of 665217 in words is "six hundred sixty-five thousand, two hundred seventeen".