668337391 has 2 divisors, whose sum is σ = 668337392. Its totient is φ = 668337390.

The previous prime is 668337379. The next prime is 668337403. The reversal of 668337391 is 193733866.

It is a balanced prime because it is at equal distance from previous prime (668337379) and next prime (668337403).

It is a cyclic number.

It is not a de Polignac number, because 668337391 - 2⁵ = 668337359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668337991) 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, 334168695 + 334168696.

It is an arithmetic number, because the mean of its divisors is an integer number (334168696).

Almost surely, 2^668337391 is an apocalyptic number.

668337391 is a deficient number, since it is larger than the sum of its proper divisors (1).

668337391 is an equidigital number, since it uses as much as digits as its factorization.

668337391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 489888, while the sum is 46.

The square root of 668337391 is about 25852.2221675430. Note that the first 3 decimals coincide. The cubic root of 668337391 is about 874.3096120428.

The spelling of 668337391 in words is "six hundred sixty-eight million, three hundred thirty-seven thousand, three hundred ninety-one".