666226815 has 16 divisors (see below), whose sum is σ = 1068940800. Its totient is φ = 354328352.

The previous prime is 666226793. The next prime is 666226817. The reversal of 666226815 is 518622666.

It is a cyclic number.

It is not a de Polignac number, because 666226815 - 2⁵ = 666226783 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666226817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56475 + ... + 67244.

It is an arithmetic number, because the mean of its divisors is an integer number (66808800).

Almost surely, 2^666226815 is an apocalyptic number.

666226815 is a deficient number, since it is larger than the sum of its proper divisors (402713985).

666226815 is a wasteful number, since it uses less digits than its factorization.

666226815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124086.

The product of its digits is 207360, while the sum is 42.

The square root of 666226815 is about 25811.3698784082. The cubic root of 666226815 is about 873.3882995563.

It can be divided in two parts, 66622 and 6815, that added together give a palindrome (73437).

The spelling of 666226815 in words is "six hundred sixty-six million, two hundred twenty-six thousand, eight hundred fifteen".