66838909 has 8 divisors (see below), whose sum is σ = 69279320. Its totient is φ = 64431936.

The previous prime is 66838901. The next prime is 66838913. The reversal of 66838909 is 90983866.

It can be written as a sum of positive squares in 4 ways, for example, as 35366809 + 31472100 = 5947^2 + 5610^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66838909 - 2³ = 66838901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66838901) 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 in 7 ways as a sum of consecutive naturals, for example, 4254 + ... + 12319.

It is an arithmetic number, because the mean of its divisors is an integer number (8659915).

Almost surely, 2^66838909 is an apocalyptic number.

It is an amenable number.

66838909 is a deficient number, since it is larger than the sum of its proper divisors (2440411).

66838909 is a wasteful number, since it uses less digits than its factorization.

66838909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16719.

The product of its (nonzero) digits is 559872, while the sum is 49.

The square root of 66838909 is about 8175.5066509667. The cubic root of 66838909 is about 405.8290369516.

The spelling of 66838909 in words is "sixty-six million, eight hundred thirty-eight thousand, nine hundred nine".