128726721900 has 432 divisors, whose sum is σ = 480449249280. Its totient is φ = 28208217600.

The previous prime is 128726721883. The next prime is 128726721901. The reversal of 128726721900 is 9127627821.

It is a happy number.

128726721900 is a `hidden beast` number, since 1 + 287 + 267 + 21 + 90 + 0 = 666.

It is a super-2 number, since 2×128726721900² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (128726721901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 21284677 + ... + 21290723.

It is an arithmetic number, because the mean of its divisors is an integer number (1112151040).

Almost surely, 2^128726721900 is an apocalyptic number.

128726721900 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 128726721900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (240224624640).

128726721900 is an abundant number, since it is smaller than the sum of its proper divisors (351722527380).

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

128726721900 is a wasteful number, since it uses less digits than its factorization.

128726721900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6214 (or 6204 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 45.

The spelling of 128726721900 in words is "one hundred twenty-eight billion, seven hundred twenty-six million, seven hundred twenty-one thousand, nine hundred".