666213 has 8 divisors (see below), whose sum is σ = 940608. Its totient is φ = 417984.

The previous prime is 666203. The next prime is 666229. The reversal of 666213 is 312666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 666213 - 2¹⁴ = 649829 is a prime.

It is a super-2 number, since 2×666213² = 887679522738, which contains 22 as substring.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 666213.

It is not an unprimeable number, because it can be changed into a prime (666203) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6481 + ... + 6582.

It is an arithmetic number, because the mean of its divisors is an integer number (117576).

2⁶⁶⁶²¹³ is an apocalyptic number.

It is an amenable number.

666213 is a deficient number, since it is larger than the sum of its proper divisors (274395).

666213 is a wasteful number, since it uses less digits than its factorization.

666213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13083.

The product of its digits is 1296, while the sum is 24.

The square root of 666213 is about 816.2187206870. The cubic root of 666213 is about 87.3382262602.

Adding to 666213 its reverse (312666), we get a palindrome (978879).

The spelling of 666213 in words is "six hundred sixty-six thousand, two hundred thirteen".