1666571287 has 2 divisors, whose sum is σ = 1666571288. Its totient is φ = 1666571286.

The previous prime is 1666571177. The next prime is 1666571303. The reversal of 1666571287 is 7821756661.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1666571287 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1666571287.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666571587) 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, 833285643 + 833285644.

It is an arithmetic number, because the mean of its divisors is an integer number (833285644).

Almost surely, 2^1666571287 is an apocalyptic number.

1666571287 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666571287 is an equidigital number, since it uses as much as digits as its factorization.

1666571287 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 846720, while the sum is 49.

The square root of 1666571287 is about 40823.6608720972. The cubic root of 1666571287 is about 1185.6084840454.

The spelling of 1666571287 in words is "one billion, six hundred sixty-six million, five hundred seventy-one thousand, two hundred eighty-seven".