665717539 has 2 divisors, whose sum is σ = 665717540. Its totient is φ = 665717538.

The previous prime is 665717491. The next prime is 665717593. The reversal of 665717539 is 935717566.

665717539 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

Together with next prime (665717593) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665717539 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 665717492 and 665717501.

It is not a weakly prime, because it can be changed into another prime (665717639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332858769 + 332858770.

It is an arithmetic number, because the mean of its divisors is an integer number (332858770).

Almost surely, 2^665717539 is an apocalyptic number.

665717539 is a deficient number, since it is larger than the sum of its proper divisors (1).

665717539 is an equidigital number, since it uses as much as digits as its factorization.

665717539 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1190700, while the sum is 49.

The square root of 665717539 is about 25801.5026500396. The cubic root of 665717539 is about 873.1656981467.

The spelling of 665717539 in words is "six hundred sixty-five million, seven hundred seventeen thousand, five hundred thirty-nine".