668866999 has 2 divisors, whose sum is σ = 668867000. Its totient is φ = 668866998.

The previous prime is 668866997. The next prime is 668867029. The reversal of 668866999 is 999668866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 668866999 - 2¹ = 668866997 is a prime.

Together with 668866997, it forms a pair of twin primes.

It is a zygodrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668866993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334433499 + 334433500.

It is an arithmetic number, because the mean of its divisors is an integer number (334433500).

Almost surely, 2^668866999 is an apocalyptic number.

668866999 is a deficient number, since it is larger than the sum of its proper divisors (1).

668866999 is an equidigital number, since it uses as much as digits as its factorization.

668866999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60466176, while the sum is 67.

The square root of 668866999 is about 25862.4631270883. The cubic root of 668866999 is about 874.5404929902.

The spelling of 668866999 in words is "six hundred sixty-eight million, eight hundred sixty-six thousand, nine hundred ninety-nine".