128005109440 has 448 divisors, whose sum is σ = 359828396928. Its totient is φ = 42939187200.

The previous prime is 128005109431. The next prime is 128005109521. The reversal of 128005109440 is 44901500821.

It is a happy number.

It is a super-2 number, since 2×128005109440² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a junction number, because it is equal to n+sod(n) for n = 128005109396 and 128005109405.

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, 379836952 + ... + 379837288.

It is an arithmetic number, because the mean of its divisors is an integer number (803188386).

Almost surely, 2^128005109440 is an apocalyptic number.

128005109440 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 128005109440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (179914198464).

128005109440 is an abundant number, since it is smaller than the sum of its proper divisors (231823287488).

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

128005109440 is a wasteful number, since it uses less digits than its factorization.

128005109440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 556 (or 546 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 34.

The spelling of 128005109440 in words is "one hundred twenty-eight billion, five million, one hundred nine thousand, four hundred forty".