128731129 has 4 divisors (see below), whose sum is σ = 128957940. Its totient is φ = 128504320.

The previous prime is 128731081. The next prime is 128731171. The reversal of 128731129 is 921137821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 921137821 = 6781 ⋅135841.

It can be written as a sum of positive squares in 2 ways, for example, as 58171129 + 70560000 = 7627^2 + 8400^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128731129 is a prime.

It is a super-2 number, since 2×128731129² = 33143407147229282, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 128731094 and 128731103.

It is not an unprimeable number, because it can be changed into a prime (128731199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 112552 + ... + 113689.

It is an arithmetic number, because the mean of its divisors is an integer number (32239485).

Almost surely, 2^128731129 is an apocalyptic number.

It is an amenable number.

128731129 is a deficient number, since it is larger than the sum of its proper divisors (226811).

128731129 is an equidigital number, since it uses as much as digits as its factorization.

128731129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226810.

The product of its digits is 6048, while the sum is 34.

The square root of 128731129 is about 11345.9741318231. The cubic root of 128731129 is about 504.9261454587.

The spelling of 128731129 in words is "one hundred twenty-eight million, seven hundred thirty-one thousand, one hundred twenty-nine".