66811729 has 2 divisors, whose sum is σ = 66811730. Its totient is φ = 66811728.

The previous prime is 66811709. The next prime is 66811741. The reversal of 66811729 is 92711866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65173329 + 1638400 = 8073^2 + 1280^2 .

It is a cyclic number.

It is not a de Polignac number, because 66811729 - 2¹⁵ = 66778961 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66811691 and 66811700.

It is not a weakly prime, because it can be changed into another prime (66811709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33405864 + 33405865.

It is an arithmetic number, because the mean of its divisors is an integer number (33405865).

Almost surely, 2^66811729 is an apocalyptic number.

It is an amenable number.

66811729 is a deficient number, since it is larger than the sum of its proper divisors (1).

66811729 is an equidigital number, since it uses as much as digits as its factorization.

66811729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 40.

The square root of 66811729 is about 8173.8441996407. The cubic root of 66811729 is about 405.7740194530.

The spelling of 66811729 in words is "sixty-six million, eight hundred eleven thousand, seven hundred twenty-nine".