128027709 has 14 divisors (see below), whose sum is σ = 191954846. Its totient is φ = 85351320.

The previous prime is 128027677. The next prime is 128027743. The reversal of 128027709 is 907720821.

It can be written as a sum of positive squares in only one way, i.e., 124947684 + 3080025 = 11178^2 + 1755^2 .

It is not a de Polignac number, because 128027709 - 2⁵ = 128027677 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 (128027609) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 87082 + ... + 88539.

Almost surely, 2^128027709 is an apocalyptic number.

It is an amenable number.

128027709 is a deficient number, since it is larger than the sum of its proper divisors (63927137).

128027709 is an frugal number, since it uses more digits than its factorization.

128027709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175639 (or 175624 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 128027709 is about 11314.9330090814. The cubic root of 128027709 is about 504.0047831179.

The spelling of 128027709 in words is "one hundred twenty-eight million, twenty-seven thousand, seven hundred nine".