666656066 has 4 divisors (see below), whose sum is σ = 999984102. Its totient is φ = 333328032.

The previous prime is 666656057. The next prime is 666656113. The reversal of 666656066 is 660656666.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 377486041 + 289170025 = 19429^2 + 17005^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 666656066.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166664015 + ... + 166664018.

Almost surely, 2^666656066 is an apocalyptic number.

666656066 is a deficient number, since it is larger than the sum of its proper divisors (333328036).

666656066 is a wasteful number, since it uses less digits than its factorization.

666656066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333328035.

The product of its (nonzero) digits is 1399680, while the sum is 47.

The square root of 666656066 is about 25819.6836928728. The cubic root of 666656066 is about 873.5758344441.

The spelling of 666656066 in words is "six hundred sixty-six million, six hundred fifty-six thousand, sixty-six".