128809842 has 16 divisors (see below), whose sum is σ = 294422592. Its totient is φ = 36802800.

The previous prime is 128809831. The next prime is 128809847. The reversal of 128809842 is 248908821.

It is a Harshad number since it is a multiple of its sum of digits (42), and also a Moran number because the ratio is a prime number: 3066901 = 128809842 / (1 + 2 + 8 + 8 + 0 + 9 + 8 + 4 + 2).

It is a junction number, because it is equal to n+sod(n) for n = 128809794 and 128809803.

It is not an unprimeable number, because it can be changed into a prime (128809847) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1533409 + ... + 1533492.

It is an arithmetic number, because the mean of its divisors is an integer number (18401412).

Almost surely, 2^128809842 is an apocalyptic number.

128809842 is an abundant number, since it is smaller than the sum of its proper divisors (165612750).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

128809842 is a wasteful number, since it uses less digits than its factorization.

128809842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3066913.

The product of its (nonzero) digits is 73728, while the sum is 42.

The square root of 128809842 is about 11349.4423651561. The cubic root of 128809842 is about 505.0290373134.

It can be divided in two parts, 12880 and 9842, that added together give a palindrome (22722).

The spelling of 128809842 in words is "one hundred twenty-eight million, eight hundred nine thousand, eight hundred forty-two".