665986117 has 2 divisors, whose sum is σ = 665986118. Its totient is φ = 665986116.

The previous prime is 665986109. The next prime is 665986121. The reversal of 665986117 is 711689566.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 665949636 + 36481 = 25806^2 + 191^2 .

It is a cyclic number.

It is not a de Polignac number, because 665986117 - 2³ = 665986109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665986127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332993058 + 332993059.

It is an arithmetic number, because the mean of its divisors is an integer number (332993059).

Almost surely, 2^665986117 is an apocalyptic number.

It is an amenable number.

665986117 is a deficient number, since it is larger than the sum of its proper divisors (1).

665986117 is an equidigital number, since it uses as much as digits as its factorization.

665986117 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 544320, while the sum is 49.

The square root of 665986117 is about 25806.7068220647. The cubic root of 665986117 is about 873.2831060826.

The spelling of 665986117 in words is "six hundred sixty-five million, nine hundred eighty-six thousand, one hundred seventeen".