66838913 has 2 divisors, whose sum is σ = 66838914. Its totient is φ = 66838912.

The previous prime is 66838901. The next prime is 66838921. The reversal of 66838913 is 31983866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50452609 + 16386304 = 7103^2 + 4048^2 .

It is a cyclic number.

It is not a de Polignac number, because 66838913 - 2¹⁰ = 66837889 is a prime.

It is not a weakly prime, because it can be changed into another prime (66838963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33419456 + 33419457.

It is an arithmetic number, because the mean of its divisors is an integer number (33419457).

Almost surely, 2^66838913 is an apocalyptic number.

It is an amenable number.

66838913 is a deficient number, since it is larger than the sum of its proper divisors (1).

66838913 is an equidigital number, since it uses as much as digits as its factorization.

66838913 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 186624, while the sum is 44.

The square root of 66838913 is about 8175.5068955998. The cubic root of 66838913 is about 405.8290450472.

The spelling of 66838913 in words is "sixty-six million, eight hundred thirty-eight thousand, nine hundred thirteen".