128403720 has 96 divisors (see below), whose sum is σ = 441880920. Its totient is φ = 32225280.

The previous prime is 128403679. The next prime is 128403721. The reversal of 128403720 is 27304821.

It can be written as a sum of positive squares in 4 ways, for example, as 116251524 + 12152196 = 10782^2 + 3486^2 .

It is not an unprimeable number, because it can be changed into a prime (128403721) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4371 + ... + 16610.

Almost surely, 2^128403720 is an apocalyptic number.

128403720 is a gapful number since it is divisible by the number (10) 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 128403720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (220940460).

128403720 is an abundant number, since it is smaller than the sum of its proper divisors (313477200).

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

128403720 is a wasteful number, since it uses less digits than its factorization.

128403720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21015 (or 21008 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 128403720 is about 11331.5365242318. The cubic root of 128403720 is about 504.4977131709.

The spelling of 128403720 in words is "one hundred twenty-eight million, four hundred three thousand, seven hundred twenty".