665717719 has 2 divisors, whose sum is σ = 665717720. Its totient is φ = 665717718.

The previous prime is 665717711. The next prime is 665717749. The reversal of 665717719 is 917717566.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 665717719 - 2³ = 665717711 is a prime.

It is a super-2 number, since 2×665717719² = 886360162781125922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665717711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332858859 + 332858860.

It is an arithmetic number, because the mean of its divisors is an integer number (332858860).

Almost surely, 2^665717719 is an apocalyptic number.

665717719 is a deficient number, since it is larger than the sum of its proper divisors (1).

665717719 is an equidigital number, since it uses as much as digits as its factorization.

665717719 is an evil number, because the sum of its binary digits is even.

The product of its digits is 555660, while the sum is 49.

The square root of 665717719 is about 25801.5061382083. The cubic root of 665717719 is about 873.1657768436.

The spelling of 665717719 in words is "six hundred sixty-five million, seven hundred seventeen thousand, seven hundred nineteen".