666225556 has 6 divisors (see below), whose sum is σ = 1165894730. Its totient is φ = 333112776.

The previous prime is 666225509. The next prime is 666225559. The reversal of 666225556 is 655522666.

It can be written as a sum of positive squares in only one way, i.e., 367488900 + 298736656 = 19170^2 + 17284^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666225559) 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 as a sum of consecutive naturals, namely, 83278191 + ... + 83278198.

Almost surely, 2^666225556 is an apocalyptic number.

It is an amenable number.

666225556 is a deficient number, since it is larger than the sum of its proper divisors (499669174).

666225556 is a wasteful number, since it uses less digits than its factorization.

666225556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166556393 (or 166556391 counting only the distinct ones).

The product of its digits is 648000, while the sum is 43.

The square root of 666225556 is about 25811.3454899197. The cubic root of 666225556 is about 873.3877493951.

The spelling of 666225556 in words is "six hundred sixty-six million, two hundred twenty-five thousand, five hundred fifty-six".