668194237 has 2 divisors, whose sum is σ = 668194238. Its totient is φ = 668194236.

The previous prime is 668194217. The next prime is 668194271. The reversal of 668194237 is 732491866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 411521796 + 256672441 = 20286^2 + 16021^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668194237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668194207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334097118 + 334097119.

It is an arithmetic number, because the mean of its divisors is an integer number (334097119).

Almost surely, 2^668194237 is an apocalyptic number.

It is an amenable number.

668194237 is a deficient number, since it is larger than the sum of its proper divisors (1).

668194237 is an equidigital number, since it uses as much as digits as its factorization.

668194237 is an evil number, because the sum of its binary digits is even.

The product of its digits is 435456, while the sum is 46.

The square root of 668194237 is about 25849.4533211053. The cubic root of 668194237 is about 874.2471835662.

The spelling of 668194237 in words is "six hundred sixty-eight million, one hundred ninety-four thousand, two hundred thirty-seven".