666242666 has 4 divisors (see below), whose sum is σ = 999364002. Its totient is φ = 333121332.

The previous prime is 666242663. The next prime is 666242677.

666242666 is nontrivially palindromic in base 10.

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., 514337041 + 151905625 = 22679^2 + 12325^2 .

It is not an unprimeable number, because it can be changed into a prime (666242663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166560665 + ... + 166560668.

Almost surely, 2^666242666 is an apocalyptic number.

666242666 is a deficient number, since it is larger than the sum of its proper divisors (333121336).

666242666 is a wasteful number, since it uses less digits than its factorization.

666242666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333121335.

The product of its digits is 746496, while the sum is 44.

The square root of 666242666 is about 25811.6769311876. The cubic root of 666242666 is about 873.3952261104.

The spelling of 666242666 in words is "six hundred sixty-six million, two hundred forty-two thousand, six hundred sixty-six".