128109277 has 4 divisors (see below), whose sum is σ = 128478816. Its totient is φ = 127739740.

The previous prime is 128109271. The next prime is 128109307. The reversal of 128109277 is 772901821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 128109277 - 2²³ = 119720669 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 (128109271) 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, 184249 + ... + 184942.

It is an arithmetic number, because the mean of its divisors is an integer number (32119704).

Almost surely, 2^128109277 is an apocalyptic number.

It is an amenable number.

128109277 is a deficient number, since it is larger than the sum of its proper divisors (369539).

128109277 is an equidigital number, since it uses as much as digits as its factorization.

128109277 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 369538.

The product of its (nonzero) digits is 14112, while the sum is 37.

The square root of 128109277 is about 11318.5368754093. The cubic root of 128109277 is about 504.1117962399. Note that the first 3 decimals are identical.

The spelling of 128109277 in words is "one hundred twenty-eight million, one hundred nine thousand, two hundred seventy-seven".