665820593 has 2 divisors, whose sum is σ = 665820594. Its totient is φ = 665820592.

The previous prime is 665820539. The next prime is 665820619. The reversal of 665820593 is 395028566.

It is a happy number.

Together with previous prime (665820539) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 561310864 + 104509729 = 23692^2 + 10223^2 .

It is a cyclic number.

It is not a de Polignac number, because 665820593 - 2¹² = 665816497 is a prime.

It is not a weakly prime, because it can be changed into another prime (665820523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332910296 + 332910297.

It is an arithmetic number, because the mean of its divisors is an integer number (332910297).

Almost surely, 2^665820593 is an apocalyptic number.

It is an amenable number.

665820593 is a deficient number, since it is larger than the sum of its proper divisors (1).

665820593 is an equidigital number, since it uses as much as digits as its factorization.

665820593 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 388800, while the sum is 44.

The square root of 665820593 is about 25803.4996269886. The cubic root of 665820593 is about 873.2107515764.

The spelling of 665820593 in words is "six hundred sixty-five million, eight hundred twenty thousand, five hundred ninety-three".