665717489 has 2 divisors, whose sum is σ = 665717490. Its totient is φ = 665717488.

The previous prime is 665717477. The next prime is 665717491. The reversal of 665717489 is 984717566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 634636864 + 31080625 = 25192^2 + 5575^2 .

It is a cyclic number.

It is not a de Polignac number, because 665717489 - 2¹⁶ = 665651953 is a prime.

Together with 665717491, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 665717489.

It is not a weakly prime, because it can be changed into another prime (665710489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332858744 + 332858745.

It is an arithmetic number, because the mean of its divisors is an integer number (332858745).

Almost surely, 2^665717489 is an apocalyptic number.

It is an amenable number.

665717489 is a deficient number, since it is larger than the sum of its proper divisors (1).

665717489 is an equidigital number, since it uses as much as digits as its factorization.

665717489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2540160, while the sum is 53.

The square root of 665717489 is about 25801.5016811038. The cubic root of 665717489 is about 873.1656762864.

The spelling of 665717489 in words is "six hundred sixty-five million, seven hundred seventeen thousand, four hundred eighty-nine".