666906679 has 2 divisors, whose sum is σ = 666906680. Its totient is φ = 666906678.

The previous prime is 666906673. The next prime is 666906701. The reversal of 666906679 is 976609666.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 666906679 - 2³ = 666906671 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666906671) 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, 333453339 + 333453340.

It is an arithmetic number, because the mean of its divisors is an integer number (333453340).

Almost surely, 2^666906679 is an apocalyptic number.

666906679 is a deficient number, since it is larger than the sum of its proper divisors (1).

666906679 is an equidigital number, since it uses as much as digits as its factorization.

666906679 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4408992, while the sum is 55.

The square root of 666906679 is about 25824.5363753156. The cubic root of 666906679 is about 873.6852872008.

The spelling of 666906679 in words is "six hundred sixty-six million, nine hundred six thousand, six hundred seventy-nine".