128422728 has 144 divisors (see below), whose sum is σ = 410143500. Its totient is φ = 36191232.

The previous prime is 128422727. The next prime is 128422733. The reversal of 128422728 is 827224821.

It can be written as a sum of positive squares in 2 ways, for example, as 127644804 + 777924 = 11298^2 + 882^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 128422692 and 128422701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128422727) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 313788 + ... + 314196.

Almost surely, 2^128422728 is an apocalyptic number.

128422728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 128422728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (205071750).

128422728 is an abundant number, since it is smaller than the sum of its proper divisors (281720772).

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

128422728 is a wasteful number, since it uses less digits than its factorization.

128422728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 524 (or 510 counting only the distinct ones).

The product of its digits is 28672, while the sum is 36.

The square root of 128422728 is about 11332.3752144023. The cubic root of 128422728 is about 504.5226060618.

The spelling of 128422728 in words is "one hundred twenty-eight million, four hundred twenty-two thousand, seven hundred twenty-eight".