1186665661 has 2 divisors, whose sum is σ = 1186665662. Its totient is φ = 1186665660.

The previous prime is 1186665559. The next prime is 1186665673. The reversal of 1186665661 is 1665666811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1045293561 + 141372100 = 32331^2 + 11890^2 .

It is an emirp because it is prime and its reverse (1665666811) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1186665661 - 2⁹ = 1186665149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1186665061) 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, 593332830 + 593332831.

It is an arithmetic number, because the mean of its divisors is an integer number (593332831).

Almost surely, 2^1186665661 is an apocalyptic number.

It is an amenable number.

1186665661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1186665661 is an equidigital number, since it uses as much as digits as its factorization.

1186665661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 311040, while the sum is 46.

The square root of 1186665661 is about 34448.0138904988. The cubic root of 1186665661 is about 1058.7078300407.

The spelling of 1186665661 in words is "one billion, one hundred eighty-six million, six hundred sixty-five thousand, six hundred sixty-one".