667985771 has 2 divisors, whose sum is σ = 667985772. Its totient is φ = 667985770.

The previous prime is 667985741. The next prime is 667985789. The reversal of 667985771 is 177589766.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 667985771 - 2⁶ = 667985707 is a prime.

It is not a weakly prime, because it can be changed into another prime (667985701) 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, 333992885 + 333992886.

It is an arithmetic number, because the mean of its divisors is an integer number (333992886).

Almost surely, 2^667985771 is an apocalyptic number.

667985771 is a deficient number, since it is larger than the sum of its proper divisors (1).

667985771 is an equidigital number, since it uses as much as digits as its factorization.

667985771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4445280, while the sum is 56.

The square root of 667985771 is about 25845.4206969049. The cubic root of 667985771 is about 874.1562570263.

The spelling of 667985771 in words is "six hundred sixty-seven million, nine hundred eighty-five thousand, seven hundred seventy-one".