666661159 has 2 divisors, whose sum is σ = 666661160. Its totient is φ = 666661158.

The previous prime is 666661147. The next prime is 666661201. The reversal of 666661159 is 951166666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 666661159 - 2¹⁹ = 666136871 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666661109) 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, 333330579 + 333330580.

It is an arithmetic number, because the mean of its divisors is an integer number (333330580).

Almost surely, 2^666661159 is an apocalyptic number.

666661159 is a deficient number, since it is larger than the sum of its proper divisors (1).

666661159 is an equidigital number, since it uses as much as digits as its factorization.

666661159 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 349920, while the sum is 46.

The square root of 666661159 is about 25819.7823189894. The cubic root of 666661159 is about 873.5780590347.

It can be divided in two parts, 666 and 661159, that added together give a triangular number (661825 = T₁₁₅₀).

The spelling of 666661159 in words is "six hundred sixty-six million, six hundred sixty-one thousand, one hundred fifty-nine".