666286817 has 4 divisors (see below), whose sum is σ = 761470656. Its totient is φ = 571102980.

The previous prime is 666286783. The next prime is 666286853. The reversal of 666286817 is 718682666.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 666286817 - 2¹⁸ = 666024673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666286877) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47591909 + ... + 47591922.

It is an arithmetic number, because the mean of its divisors is an integer number (190367664).

Almost surely, 2^666286817 is an apocalyptic number.

It is an amenable number.

666286817 is a deficient number, since it is larger than the sum of its proper divisors (95183839).

666286817 is an equidigital number, since it uses as much as digits as its factorization.

666286817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95183838.

The product of its digits is 1161216, while the sum is 50.

The square root of 666286817 is about 25812.5321694715. The cubic root of 666286817 is about 873.4145185908.

The spelling of 666286817 in words is "six hundred sixty-six million, two hundred eighty-six thousand, eight hundred seventeen".