66682813 has 2 divisors, whose sum is σ = 66682814. Its totient is φ = 66682812.

The previous prime is 66682807. The next prime is 66682841. The reversal of 66682813 is 31828666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49815364 + 16867449 = 7058^2 + 4107^2 .

It is a cyclic number.

It is not a de Polignac number, because 66682813 - 2¹⁷ = 66551741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66682883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33341406 + 33341407.

It is an arithmetic number, because the mean of its divisors is an integer number (33341407).

Almost surely, 2^66682813 is an apocalyptic number.

It is an amenable number.

66682813 is a deficient number, since it is larger than the sum of its proper divisors (1).

66682813 is an equidigital number, since it uses as much as digits as its factorization.

66682813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82944, while the sum is 40.

The square root of 66682813 is about 8165.9545063636. The cubic root of 66682813 is about 405.5128654828.

The spelling of 66682813 in words is "sixty-six million, six hundred eighty-two thousand, eight hundred thirteen".