66931643 has 2 divisors, whose sum is σ = 66931644. Its totient is φ = 66931642.

The previous prime is 66931637. The next prime is 66931673. The reversal of 66931643 is 34613966.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66931643 - 2¹² = 66927547 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66931597 and 66931606.

It is not a weakly prime, because it can be changed into another prime (66931673) 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, 33465821 + 33465822.

It is an arithmetic number, because the mean of its divisors is an integer number (33465822).

Almost surely, 2^66931643 is an apocalyptic number.

66931643 is a deficient number, since it is larger than the sum of its proper divisors (1).

66931643 is an equidigital number, since it uses as much as digits as its factorization.

66931643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69984, while the sum is 38.

The square root of 66931643 is about 8181.1761379401. The cubic root of 66931643 is about 406.0166360562.

The spelling of 66931643 in words is "sixty-six million, nine hundred thirty-one thousand, six hundred forty-three".