866129729 has 2 divisors, whose sum is σ = 866129730. Its totient is φ = 866129728.

The previous prime is 866129723. The next prime is 866129731. The reversal of 866129729 is 927921668.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 837986704 + 28143025 = 28948^2 + 5305^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-866129729 is a prime.

It is a super-2 number, since 2×866129729² = 1500361414915226882, which contains 22 as substring.

Together with 866129731, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (866129723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433064864 + 433064865.

It is an arithmetic number, because the mean of its divisors is an integer number (433064865).

Almost surely, 2^866129729 is an apocalyptic number.

It is an amenable number.

866129729 is a deficient number, since it is larger than the sum of its proper divisors (1).

866129729 is an equidigital number, since it uses as much as digits as its factorization.

866129729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 50.

The square root of 866129729 is about 29430.0820420195. The cubic root of 866129729 is about 953.2225663792. Note that the first 3 decimals are identical.

The spelling of 866129729 in words is "eight hundred sixty-six million, one hundred twenty-nine thousand, seven hundred twenty-nine".