666727666 has 12 divisors (see below), whose sum is σ = 1099274526. Its totient is φ = 303057920.

The previous prime is 666727639. The next prime is 666727667.

666727666 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 606587641 + 60140025 = 24629^2 + 7755^2 .

It is not an unprimeable number, because it can be changed into a prime (666727667) 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 5 ways as a sum of consecutive naturals, for example, 1377295 + ... + 1377778.

Almost surely, 2^666727666 is an apocalyptic number.

666727666 is a deficient number, since it is larger than the sum of its proper divisors (432546860).

666727666 is a wasteful number, since it uses less digits than its factorization.

666727666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2755097 (or 2755086 counting only the distinct ones).

The product of its digits is 4572288, while the sum is 52.

The square root of 666727666 is about 25821.0701947073. The cubic root of 666727666 is about 873.6071078367.

The spelling of 666727666 in words is "six hundred sixty-six million, seven hundred twenty-seven thousand, six hundred sixty-six".