666887789 has 2 divisors, whose sum is σ = 666887790. Its totient is φ = 666887788.

The previous prime is 666887723. The next prime is 666887863. The reversal of 666887789 is 987788666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 619512100 + 47375689 = 24890^2 + 6883^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666887789 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666887189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333443894 + 333443895.

It is an arithmetic number, because the mean of its divisors is an integer number (333443895).

Almost surely, 2^666887789 is an apocalyptic number.

It is an amenable number.

666887789 is a deficient number, since it is larger than the sum of its proper divisors (1).

666887789 is an equidigital number, since it uses as much as digits as its factorization.

666887789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48771072, while the sum is 65.

The square root of 666887789 is about 25824.1706352789. The cubic root of 666887789 is about 873.6770381352.

The spelling of 666887789 in words is "six hundred sixty-six million, eight hundred eighty-seven thousand, seven hundred eighty-nine".