665509993 has 2 divisors, whose sum is σ = 665509994. Its totient is φ = 665509992.

The previous prime is 665509967. The next prime is 665510057. The reversal of 665509993 is 399905566.

665509993 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 645769744 + 19740249 = 25412^2 + 4443^2 .

It is a cyclic number.

It is not a de Polignac number, because 665509993 - 2⁵ = 665509961 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 665509993.

It is not a weakly prime, because it can be changed into another prime (665509913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332754996 + 332754997.

It is an arithmetic number, because the mean of its divisors is an integer number (332754997).

Almost surely, 2^665509993 is an apocalyptic number.

It is an amenable number.

665509993 is a deficient number, since it is larger than the sum of its proper divisors (1).

665509993 is an equidigital number, since it uses as much as digits as its factorization.

665509993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1968300, while the sum is 52.

The square root of 665509993 is about 25797.4803614617. The cubic root of 665509993 is about 873.0749485052.

The spelling of 665509993 in words is "six hundred sixty-five million, five hundred nine thousand, nine hundred ninety-three".