66871729 has 2 divisors, whose sum is σ = 66871730. Its totient is φ = 66871728.

The previous prime is 66871711. The next prime is 66871747. The reversal of 66871729 is 92717866.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (66871711) and next prime (66871747).

It can be written as a sum of positive squares in only one way, i.e., 58110129 + 8761600 = 7623^2 + 2960^2 .

It is a cyclic number.

It is not a de Polignac number, because 66871729 - 2⁷ = 66871601 is a prime.

It is not a weakly prime, because it can be changed into another prime (66871759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33435864 + 33435865.

It is an arithmetic number, because the mean of its divisors is an integer number (33435865).

Almost surely, 2^66871729 is an apocalyptic number.

It is an amenable number.

66871729 is a deficient number, since it is larger than the sum of its proper divisors (1).

66871729 is an equidigital number, since it uses as much as digits as its factorization.

66871729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 254016, while the sum is 46.

The square root of 66871729 is about 8177.5136196768. The cubic root of 66871729 is about 405.8954510095.

It can be divided in two parts, 668717 and 29, that added together give a triangular number (668746 = T₁₁₅₆).

The spelling of 66871729 in words is "sixty-six million, eight hundred seventy-one thousand, seven hundred twenty-nine".