665719489 has 2 divisors, whose sum is σ = 665719490. Its totient is φ = 665719488.

The previous prime is 665719487. The next prime is 665719529. The reversal of 665719489 is 984917566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 660078864 + 5640625 = 25692^2 + 2375^2 .

It is a cyclic number.

It is not a de Polignac number, because 665719489 - 2¹ = 665719487 is a prime.

It is a super-2 number, since 2×665719489² = 886364876068842242, which contains 22 as substring.

Together with 665719487, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (665719487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332859744 + 332859745.

It is an arithmetic number, because the mean of its divisors is an integer number (332859745).

Almost surely, 2^665719489 is an apocalyptic number.

It is an amenable number.

665719489 is a deficient number, since it is larger than the sum of its proper divisors (1).

665719489 is an equidigital number, since it uses as much as digits as its factorization.

665719489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3265920, while the sum is 55.

The square root of 665719489 is about 25801.5404385087. The cubic root of 665719489 is about 873.1665506962.

The spelling of 665719489 in words is "six hundred sixty-five million, seven hundred nineteen thousand, four hundred eighty-nine".