128308749 has 4 divisors (see below), whose sum is σ = 171078336. Its totient is φ = 85539164.

The previous prime is 128308727. The next prime is 128308751. The reversal of 128308749 is 947803821.

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 128308749 - 2²⁴ = 111531533 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 128308749.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128308709) 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, 21384789 + ... + 21384794.

It is an arithmetic number, because the mean of its divisors is an integer number (42769584).

Almost surely, 2^128308749 is an apocalyptic number.

It is an amenable number.

128308749 is a deficient number, since it is larger than the sum of its proper divisors (42769587).

128308749 is an equidigital number, since it uses as much as digits as its factorization.

128308749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42769586.

The product of its (nonzero) digits is 96768, while the sum is 42.

The square root of 128308749 is about 11327.3451876422. The cubic root of 128308749 is about 504.3733022642.

The spelling of 128308749 in words is "one hundred twenty-eight million, three hundred eight thousand, seven hundred forty-nine".