665544361 has 2 divisors, whose sum is σ = 665544362. Its totient is φ = 665544360.

The previous prime is 665544337. The next prime is 665544391. The reversal of 665544361 is 163445566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 615982761 + 49561600 = 24819^2 + 7040^2 .

It is a cyclic number.

It is not a de Polignac number, because 665544361 - 2⁹ = 665543849 is a prime.

It is equal to p_34559194 and since 665544361 and 34559194 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (665544391) 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, 332772180 + 332772181.

It is an arithmetic number, because the mean of its divisors is an integer number (332772181).

Almost surely, 2^665544361 is an apocalyptic number.

It is an amenable number.

665544361 is a deficient number, since it is larger than the sum of its proper divisors (1).

665544361 is an equidigital number, since it uses as much as digits as its factorization.

665544361 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 259200, while the sum is 40.

The square root of 665544361 is about 25798.1464644265. The cubic root of 665544361 is about 873.0899772419.

The spelling of 665544361 in words is "six hundred sixty-five million, five hundred forty-four thousand, three hundred sixty-one".