66813689 has 16 divisors (see below), whose sum is σ = 74556288. Its totient is φ = 59549952.

The previous prime is 66813679. The next prime is 66813707. The reversal of 66813689 is 98631866.

It is a cyclic number.

It is not a de Polignac number, because 66813689 - 2⁸ = 66813433 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66813619) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41039 + ... + 42635.

It is an arithmetic number, because the mean of its divisors is an integer number (4659768).

Almost surely, 2^66813689 is an apocalyptic number.

It is an amenable number.

66813689 is a deficient number, since it is larger than the sum of its proper divisors (7742599).

66813689 is a wasteful number, since it uses less digits than its factorization.

66813689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1744.

The product of its digits is 373248, while the sum is 47.

The square root of 66813689 is about 8173.9640933882. The cubic root of 66813689 is about 405.7779873656. Note that the first 3 decimals are identical.

The spelling of 66813689 in words is "sixty-six million, eight hundred thirteen thousand, six hundred eighty-nine".