668998787 has 2 divisors, whose sum is σ = 668998788. Its totient is φ = 668998786.

The previous prime is 668998783. The next prime is 668998829. The reversal of 668998787 is 787899866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 668998787 - 2² = 668998783 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (668998783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334499393 + 334499394.

It is an arithmetic number, because the mean of its divisors is an integer number (334499394).

Almost surely, 2^668998787 is an apocalyptic number.

668998787 is a deficient number, since it is larger than the sum of its proper divisors (1).

668998787 is an equidigital number, since it uses as much as digits as its factorization.

668998787 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 73156608, while the sum is 68.

The square root of 668998787 is about 25865.0108640998. The cubic root of 668998787 is about 874.5979266175.

The spelling of 668998787 in words is "six hundred sixty-eight million, nine hundred ninety-eight thousand, seven hundred eighty-seven".