667486646821 has 2 divisors, whose sum is σ = 667486646822. Its totient is φ = 667486646820.

The previous prime is 667486646807. The next prime is 667486646833. The reversal of 667486646821 is 128646684766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 627850216900 + 39636429921 = 792370^2 + 199089^2 .

It is a cyclic number.

It is not a de Polignac number, because 667486646821 - 2⁷ = 667486646693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667486646861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333743323410 + 333743323411.

It is an arithmetic number, because the mean of its divisors is an integer number (333743323411).

Almost surely, 2^667486646821 is an apocalyptic number.

It is an amenable number.

667486646821 is a deficient number, since it is larger than the sum of its proper divisors (1).

667486646821 is an equidigital number, since it uses as much as digits as its factorization.

667486646821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 111476736, while the sum is 64.

The spelling of 667486646821 in words is "six hundred sixty-seven billion, four hundred eighty-six million, six hundred forty-six thousand, eight hundred twenty-one".