66864139 has 2 divisors, whose sum is σ = 66864140. Its totient is φ = 66864138.

The previous prime is 66864079. The next prime is 66864181. The reversal of 66864139 is 93146866.

66864139 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66864139 - 2¹¹ = 66862091 is a prime.

It is a super-2 number, since 2×66864139² = 8941626168422642, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66864095 and 66864104.

It is not a weakly prime, because it can be changed into another prime (66834139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33432069 + 33432070.

It is an arithmetic number, because the mean of its divisors is an integer number (33432070).

Almost surely, 2^66864139 is an apocalyptic number.

66864139 is a deficient number, since it is larger than the sum of its proper divisors (1).

66864139 is an equidigital number, since it uses as much as digits as its factorization.

66864139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 186624, while the sum is 43.

The square root of 66864139 is about 8177.0495290172. The cubic root of 66864139 is about 405.8800939317.

The spelling of 66864139 in words is "sixty-six million, eight hundred sixty-four thousand, one hundred thirty-nine".