128727781632 has 180 divisors, whose sum is σ = 386297581516. Its totient is φ = 42634874880.

The previous prime is 128727781601. The next prime is 128727781639. The reversal of 128727781632 is 236187727821.

It can be written as a sum of positive squares in 2 ways, for example, as 13138661376 + 115589120256 = 114624^2 + 339984^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (128727781639) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3235782 + ... + 3275322.

Almost surely, 2^128727781632 is an apocalyptic number.

128727781632 is a gapful number since it is divisible by the number (12) 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 128727781632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (193148790758).

128727781632 is an abundant number, since it is smaller than the sum of its proper divisors (257569799884).

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

128727781632 is an equidigital number, since it uses as much as digits as its factorization.

128727781632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39726 (or 39703 counting only the distinct ones).

The product of its digits is 3161088, while the sum is 54.

The spelling of 128727781632 in words is "one hundred twenty-eight billion, seven hundred twenty-seven million, seven hundred eighty-one thousand, six hundred thirty-two".