665390617 has 2 divisors, whose sum is σ = 665390618. Its totient is φ = 665390616.

The previous prime is 665390563. The next prime is 665390639. The reversal of 665390617 is 716093566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 665072521 + 318096 = 25789^2 + 564^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665390617 is a prime.

It is not a weakly prime, because it can be changed into another prime (665390657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332695308 + 332695309.

It is an arithmetic number, because the mean of its divisors is an integer number (332695309).

Almost surely, 2^665390617 is an apocalyptic number.

It is an amenable number.

665390617 is a deficient number, since it is larger than the sum of its proper divisors (1).

665390617 is an equidigital number, since it uses as much as digits as its factorization.

665390617 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 204120, while the sum is 43.

The square root of 665390617 is about 25795.1665433662. The cubic root of 665390617 is about 873.0227427139.

The spelling of 665390617 in words is "six hundred sixty-five million, three hundred ninety thousand, six hundred seventeen".