66835681 has 12 divisors (see below), whose sum is σ = 73671892. Its totient is φ = 60588000.

The previous prime is 66835679. The next prime is 66835709. The reversal of 66835681 is 18653866.

It can be written as a sum of positive squares in 2 ways, for example, as 32718400 + 34117281 = 5720^2 + 5841^2 .

It is not a de Polignac number, because 66835681 - 2¹ = 66835679 is a prime.

It is a super-2 number, since 2×66835681² = 8934016509467522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66835621) 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 in 11 ways as a sum of consecutive naturals, for example, 64951 + ... + 65971.

Almost surely, 2^66835681 is an apocalyptic number.

It is an amenable number.

66835681 is a deficient number, since it is larger than the sum of its proper divisors (6836211).

66835681 is a wasteful number, since it uses less digits than its factorization.

66835681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1584 (or 1573 counting only the distinct ones).

The product of its digits is 207360, while the sum is 43.

The square root of 66835681 is about 8175.3092296255. The cubic root of 66835681 is about 405.8225036451.

The spelling of 66835681 in words is "sixty-six million, eight hundred thirty-five thousand, six hundred eighty-one".