66401729 has 2 divisors, whose sum is σ = 66401730. Its totient is φ = 66401728.

The previous prime is 66401719. The next prime is 66401747. The reversal of 66401729 is 92710466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66259600 + 142129 = 8140^2 + 377^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66401729 is a prime.

It is a super-3 number, since 3×66401729³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (66401719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33200864 + 33200865.

It is an arithmetic number, because the mean of its divisors is an integer number (33200865).

Almost surely, 2^66401729 is an apocalyptic number.

It is an amenable number.

66401729 is a deficient number, since it is larger than the sum of its proper divisors (1).

66401729 is an equidigital number, since it uses as much as digits as its factorization.

66401729 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 66401729 is about 8148.7256058846. The cubic root of 66401729 is about 404.9422851253.

The spelling of 66401729 in words is "sixty-six million, four hundred one thousand, seven hundred twenty-nine".