16666811257 has 2 divisors, whose sum is σ = 16666811258. Its totient is φ = 16666811256.

The previous prime is 16666811251. The next prime is 16666811269. The reversal of 16666811257 is 75211866661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14961203856 + 1705607401 = 122316^2 + 41299^2 .

It is a cyclic number.

It is not a de Polignac number, because 16666811257 - 2⁷ = 16666811129 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16666811257.

It is not a weakly prime, because it can be changed into another prime (16666811251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8333405628 + 8333405629.

It is an arithmetic number, because the mean of its divisors is an integer number (8333405629).

Almost surely, 2^16666811257 is an apocalyptic number.

It is an amenable number.

16666811257 is a deficient number, since it is larger than the sum of its proper divisors (1).

16666811257 is an equidigital number, since it uses as much as digits as its factorization.

16666811257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 725760, while the sum is 49.

The spelling of 16666811257 in words is "sixteen billion, six hundred sixty-six million, eight hundred eleven thousand, two hundred fifty-seven".