128291729 has 2 divisors, whose sum is σ = 128291730. Its totient is φ = 128291728.

The previous prime is 128291711. The next prime is 128291731. The reversal of 128291729 is 927192821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78730129 + 49561600 = 8873^2 + 7040^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128291729 is a prime.

Together with 128291731, 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 (128291789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64145864 + 64145865.

It is an arithmetic number, because the mean of its divisors is an integer number (64145865).

Almost surely, 2^128291729 is an apocalyptic number.

It is an amenable number.

128291729 is a deficient number, since it is larger than the sum of its proper divisors (1).

128291729 is an equidigital number, since it uses as much as digits as its factorization.

128291729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 41.

The square root of 128291729 is about 11326.5938834232. The cubic root of 128291729 is about 504.3509997757.

The spelling of 128291729 in words is "one hundred twenty-eight million, two hundred ninety-one thousand, seven hundred twenty-nine".