668236823 has 2 divisors, whose sum is σ = 668236824. Its totient is φ = 668236822.

The previous prime is 668236781. The next prime is 668236841. The reversal of 668236823 is 328632866.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 668236823 - 2¹² = 668232727 is a prime.

It is a super-2 number, since 2×668236823² = 893080903226266658, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668236843) 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 as a sum of consecutive naturals, namely, 334118411 + 334118412.

It is an arithmetic number, because the mean of its divisors is an integer number (334118412).

Almost surely, 2^668236823 is an apocalyptic number.

668236823 is a deficient number, since it is larger than the sum of its proper divisors (1).

668236823 is an equidigital number, since it uses as much as digits as its factorization.

668236823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 497664, while the sum is 44.

The square root of 668236823 is about 25850.2770391344. The cubic root of 668236823 is about 874.2657559601.

The spelling of 668236823 in words is "six hundred sixty-eight million, two hundred thirty-six thousand, eight hundred twenty-three".