128719765 has 4 divisors (see below), whose sum is σ = 154463724. Its totient is φ = 102975808.

The previous prime is 128719763. The next prime is 128719771. The reversal of 128719765 is 567917821.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 567917821 = 149 ⋅3811529.

It can be written as a sum of positive squares in 2 ways, for example, as 100140049 + 28579716 = 10007^2 + 5346^2 .

It is a cyclic number.

It is not a de Polignac number, because 128719765 - 2¹ = 128719763 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 (128719763) 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, 12871972 + ... + 12871981.

It is an arithmetic number, because the mean of its divisors is an integer number (38615931).

Almost surely, 2^128719765 is an apocalyptic number.

It is an amenable number.

128719765 is a deficient number, since it is larger than the sum of its proper divisors (25743959).

128719765 is an equidigital number, since it uses as much as digits as its factorization.

128719765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25743958.

The product of its digits is 211680, while the sum is 46.

The square root of 128719765 is about 11345.4733263976. The cubic root of 128719765 is about 504.9112872303.

The spelling of 128719765 in words is "one hundred twenty-eight million, seven hundred nineteen thousand, seven hundred sixty-five".