666247 has 4 divisors (see below), whose sum is σ = 705456. Its totient is φ = 627040.

The previous prime is 666233. The next prime is 666269. The reversal of 666247 is 742666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 742666 = 2 ⋅371333.

It is a cyclic number.

It is not a de Polignac number, because 666247 - 2⁷ = 666119 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666277) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19579 + ... + 19612.

It is an arithmetic number, because the mean of its divisors is an integer number (176364).

2⁶⁶⁶²⁴⁷ is an apocalyptic number.

666247 is a deficient number, since it is larger than the sum of its proper divisors (39209).

666247 is a wasteful number, since it uses less digits than its factorization.

666247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39208.

The product of its digits is 12096, while the sum is 31.

The square root of 666247 is about 816.2395481720. The cubic root of 666247 is about 87.3397119958.

The spelling of 666247 in words is "six hundred sixty-six thousand, two hundred forty-seven".