668213243 has 2 divisors, whose sum is σ = 668213244. Its totient is φ = 668213242.

The previous prime is 668213233. The next prime is 668213257. The reversal of 668213243 is 342312866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 668213243 - 2⁶ = 668213179 is a prime.

It is equal to p_34690463 and since 668213243 and 34690463 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (668213213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334106621 + 334106622.

It is an arithmetic number, because the mean of its divisors is an integer number (334106622).

Almost surely, 2^668213243 is an apocalyptic number.

668213243 is a deficient number, since it is larger than the sum of its proper divisors (1).

668213243 is an equidigital number, since it uses as much as digits as its factorization.

668213243 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41472, while the sum is 35.

The square root of 668213243 is about 25849.8209471555. The cubic root of 668213243 is about 874.2554724656.

The spelling of 668213243 in words is "six hundred sixty-eight million, two hundred thirteen thousand, two hundred forty-three".