128129677 has 4 divisors (see below), whose sum is σ = 137985820. Its totient is φ = 118273536.

The previous prime is 128129671. The next prime is 128129699. The reversal of 128129677 is 776921821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15217801 + 112911876 = 3901^2 + 10626^2 .

It is a cyclic number.

It is not a de Polignac number, because 128129677 - 2³ = 128129669 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128129671) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4928052 + ... + 4928077.

It is an arithmetic number, because the mean of its divisors is an integer number (34496455).

Almost surely, 2^128129677 is an apocalyptic number.

It is an amenable number.

128129677 is a deficient number, since it is larger than the sum of its proper divisors (9856143).

128129677 is an equidigital number, since it uses as much as digits as its factorization.

128129677 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9856142.

The product of its digits is 84672, while the sum is 43.

The square root of 128129677 is about 11319.4380160854. The cubic root of 128129677 is about 504.1385529148.

The spelling of 128129677 in words is "one hundred twenty-eight million, one hundred twenty-nine thousand, six hundred seventy-seven".