666786857 has 16 divisors (see below), whose sum is σ = 735838080. Its totient is φ = 599184000.

The previous prime is 666786851. The next prime is 666786889. The reversal of 666786857 is 758687666.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666786857 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666786796 and 666786805.

It is not an unprimeable number, because it can be changed into a prime (666786851) 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 in 15 ways as a sum of consecutive naturals, for example, 379493 + ... + 381245.

It is an arithmetic number, because the mean of its divisors is an integer number (45989880).

Almost surely, 2^666786857 is an apocalyptic number.

It is an amenable number.

666786857 is a deficient number, since it is larger than the sum of its proper divisors (69051223).

666786857 is a wasteful number, since it uses less digits than its factorization.

666786857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2144.

The product of its digits is 20321280, while the sum is 59.

The square root of 666786857 is about 25822.2163456199. The cubic root of 666786857 is about 873.6329595454.

The spelling of 666786857 in words is "six hundred sixty-six million, seven hundred eighty-six thousand, eight hundred fifty-seven".