665265109 has 2 divisors, whose sum is σ = 665265110. Its totient is φ = 665265108.

The previous prime is 665265067. The next prime is 665265137. The reversal of 665265109 is 901562566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 545362609 + 119902500 = 23353^2 + 10950^2 .

It is a cyclic number.

It is not a de Polignac number, because 665265109 - 2¹⁷ = 665134037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665265509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332632554 + 332632555.

It is an arithmetic number, because the mean of its divisors is an integer number (332632555).

Almost surely, 2^665265109 is an apocalyptic number.

It is an amenable number.

665265109 is a deficient number, since it is larger than the sum of its proper divisors (1).

665265109 is an equidigital number, since it uses as much as digits as its factorization.

665265109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 97200, while the sum is 40.

The square root of 665265109 is about 25792.7336472891. The cubic root of 665265109 is about 872.9678485281.

The spelling of 665265109 in words is "six hundred sixty-five million, two hundred sixty-five thousand, one hundred nine".