666266647 has 4 divisors (see below), whose sum is σ = 674294040. Its totient is φ = 658239256.

The previous prime is 666266609. The next prime is 666266651. The reversal of 666266647 is 746662666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 746662666 = 2 ⋅373331333.

It is a cyclic number.

It is not a de Polignac number, because 666266647 - 2²⁷ = 532048919 is a prime.

It is a super-2 number, since 2×666266647² = 887822489809245218, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 666266647.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666266747) 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 in 3 ways as a sum of consecutive naturals, for example, 4013572 + ... + 4013737.

It is an arithmetic number, because the mean of its divisors is an integer number (168573510).

Almost surely, 2^666266647 is an apocalyptic number.

666266647 is a deficient number, since it is larger than the sum of its proper divisors (8027393).

666266647 is an equidigital number, since it uses as much as digits as its factorization.

666266647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8027392.

The product of its digits is 2612736, while the sum is 49.

The square root of 666266647 is about 25812.1414648223. The cubic root of 666266647 is about 873.4057050948.

The spelling of 666266647 in words is "six hundred sixty-six million, two hundred sixty-six thousand, six hundred forty-seven".