666943 has 4 divisors (see below), whose sum is σ = 668608. Its totient is φ = 665280.

The previous prime is 666937. The next prime is 666959. The reversal of 666943 is 349666.

666943 is nontrivially palindromic in base 15.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 666943 - 2⁹ = 666431 is a prime.

It is a Duffinian number.

It is a plaindrome in base 9.

It is a junction number, because it is equal to n+sod(n) for n = 666899 and 666908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666983) 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, 178 + ... + 1168.

It is an arithmetic number, because the mean of its divisors is an integer number (167152).

2⁶⁶⁶⁹⁴³ is an apocalyptic number.

666943 is a deficient number, since it is larger than the sum of its proper divisors (1665).

666943 is an equidigital number, since it uses as much as digits as its factorization.

666943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1664.

The product of its digits is 23328, while the sum is 34.

The square root of 666943 is about 816.6657823124. The cubic root of 666943 is about 87.3701147764.

The spelling of 666943 in words is "six hundred sixty-six thousand, nine hundred forty-three".