668236841 has 2 divisors, whose sum is σ = 668236842. Its totient is φ = 668236840.

The previous prime is 668236823. The next prime is 668236843. The reversal of 668236841 is 148632866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 653058025 + 15178816 = 25555^2 + 3896^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668236841 is a prime.

Together with 668236843, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 668236792 and 668236801.

It is not a weakly prime, because it can be changed into another prime (668236843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334118420 + 334118421.

It is an arithmetic number, because the mean of its divisors is an integer number (334118421).

Almost surely, 2^668236841 is an apocalyptic number.

It is an amenable number.

668236841 is a deficient number, since it is larger than the sum of its proper divisors (1).

668236841 is an equidigital number, since it uses as much as digits as its factorization.

668236841 is an evil number, because the sum of its binary digits is even.

The product of its digits is 331776, while the sum is 44.

The square root of 668236841 is about 25850.2773872932. The cubic root of 668236841 is about 874.2657638100.

The spelling of 668236841 in words is "six hundred sixty-eight million, two hundred thirty-six thousand, eight hundred forty-one".