128500000 has 84 divisors (see below), whose sum is σ = 317456874. Its totient is φ = 51200000.

The previous prime is 128499971. The next prime is 128500003. The reversal of 128500000 is 5821.

It is a happy number.

It can be written as a sum of positive squares in 7 ways, for example, as 28259856 + 100240144 = 5316^2 + 10012^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128500003) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 499872 + ... + 500128.

Almost surely, 2^128500000 is an apocalyptic number.

128500000 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 128500000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (158728437).

128500000 is an abundant number, since it is smaller than the sum of its proper divisors (188956874).

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

128500000 is an frugal number, since it uses more digits than its factorization.

128500000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297 (or 264 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 128500000 is about 11335.7840487546. The cubic root of 128500000 is about 504.6237762489.

Adding to 128500000 its reverse (5821), we get a palindrome (128505821).

It can be divided in two parts, 128 and 500000, that multiplied together give a 6-th power (64000000 = 20⁶).

The spelling of 128500000 in words is "one hundred twenty-eight million, five hundred thousand".