128609821440 has 576 divisors, whose sum is σ = 479826547200. Its totient is φ = 32579076096.

The previous prime is 128609821381. The next prime is 128609821493. The reversal of 128609821440 is 44128906821.

128609821440 is a `hidden beast` number, since 1 + 28 + 609 + 8 + 2 + 14 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

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

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 54983791 + ... + 54986129.

It is an arithmetic number, because the mean of its divisors is an integer number (833032200).

Almost surely, 2^128609821440 is an apocalyptic number.

128609821440 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 128609821440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (239913273600).

128609821440 is an abundant number, since it is smaller than the sum of its proper divisors (351216725760).

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

128609821440 is a wasteful number, since it uses less digits than its factorization.

128609821440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2449 (or 2429 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 45.

The spelling of 128609821440 in words is "one hundred twenty-eight billion, six hundred nine million, eight hundred twenty-one thousand, four hundred forty".