666666851 has 8 divisors (see below), whose sum is σ = 720721680. Its totient is φ = 614508768.

The previous prime is 666666841. The next prime is 666666853. The reversal of 666666851 is 158666666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666666851 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 666666851.

It is not an unprimeable number, because it can be changed into a prime (666666853) 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 7 ways as a sum of consecutive naturals, for example, 473456 + ... + 474861.

It is an arithmetic number, because the mean of its divisors is an integer number (90090210).

Almost surely, 2^666666851 is an apocalyptic number.

666666851 is a deficient number, since it is larger than the sum of its proper divisors (54054829).

666666851 is a wasteful number, since it uses less digits than its factorization.

666666851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 948373.

The product of its digits is 1866240, while the sum is 50.

The square root of 666666851 is about 25819.8925443155. The cubic root of 666666851 is about 873.5805452513.

The spelling of 666666851 in words is "six hundred sixty-six million, six hundred sixty-six thousand, eight hundred fifty-one".