128116865 has 4 divisors (see below), whose sum is σ = 153740244. Its totient is φ = 102493488.

The previous prime is 128116861. The next prime is 128116883. The reversal of 128116865 is 568611821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 568611821 = 41 ⋅13868581.

It can be written as a sum of positive squares in 2 ways, for example, as 91623184 + 36493681 = 9572^2 + 6041^2 .

It is a cyclic number.

It is not a de Polignac number, because 128116865 - 2² = 128116861 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128116861) 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, 12811682 + ... + 12811691.

It is an arithmetic number, because the mean of its divisors is an integer number (38435061).

Almost surely, 2^128116865 is an apocalyptic number.

It is an amenable number.

128116865 is a deficient number, since it is larger than the sum of its proper divisors (25623379).

128116865 is an equidigital number, since it uses as much as digits as its factorization.

128116865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25623378.

The product of its digits is 23040, while the sum is 38.

The square root of 128116865 is about 11318.8720727818. The cubic root of 128116865 is about 504.1217490054.

The spelling of 128116865 in words is "one hundred twenty-eight million, one hundred sixteen thousand, eight hundred sixty-five".