667688893 has 2 divisors, whose sum is σ = 667688894. Its totient is φ = 667688892.

The previous prime is 667688891. The next prime is 667688929. The reversal of 667688893 is 398886766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 665536804 + 2152089 = 25798^2 + 1467^2 .

It is a cyclic number.

It is not a de Polignac number, because 667688893 - 2¹ = 667688891 is a prime.

Together with 667688891, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667688891) 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, 333844446 + 333844447.

It is an arithmetic number, because the mean of its divisors is an integer number (333844447).

Almost surely, 2^667688893 is an apocalyptic number.

It is an amenable number.

667688893 is a deficient number, since it is larger than the sum of its proper divisors (1).

667688893 is an equidigital number, since it uses as much as digits as its factorization.

667688893 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20901888, while the sum is 61.

The square root of 667688893 is about 25839.6767201140. The cubic root of 667688893 is about 874.0267351969.

The spelling of 667688893 in words is "six hundred sixty-seven million, six hundred eighty-eight thousand, eight hundred ninety-three".