665061181 has 2 divisors, whose sum is σ = 665061182. Its totient is φ = 665061180.

The previous prime is 665061179. The next prime is 665061247. The reversal of 665061181 is 181160566.

665061181 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., 432224100 + 232837081 = 20790^2 + 15259^2 .

It is a cyclic number.

It is not a de Polignac number, because 665061181 - 2¹ = 665061179 is a prime.

It is a super-2 number, since 2×665061181² = 884612748946229522, which contains 22 as substring.

Together with 665061179, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665061121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332530590 + 332530591.

It is an arithmetic number, because the mean of its divisors is an integer number (332530591).

Almost surely, 2^665061181 is an apocalyptic number.

It is an amenable number.

665061181 is a deficient number, since it is larger than the sum of its proper divisors (1).

665061181 is an equidigital number, since it uses as much as digits as its factorization.

665061181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8640, while the sum is 34.

The square root of 665061181 is about 25788.7801378817. The cubic root of 665061181 is about 872.8786405927.

The spelling of 665061181 in words is "six hundred sixty-five million, sixty-one thousand, one hundred eighty-one".