128940840 has 192 divisors, whose sum is σ = 504316800. Its totient is φ = 27910656.

The previous prime is 128940827. The next prime is 128940857. The reversal of 128940840 is 48049821.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 128940795 and 128940804.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 46534 + ... + 49226.

It is an arithmetic number, because the mean of its divisors is an integer number (2626650).

Almost surely, 2^128940840 is an apocalyptic number.

128940840 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 128940840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (252158400).

128940840 is an abundant number, since it is smaller than the sum of its proper divisors (375375960).

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

128940840 is a wasteful number, since it uses less digits than its factorization.

128940840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2736 (or 2729 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 128940840 is about 11355.2120191567. The cubic root of 128940840 is about 505.2001820496.

The spelling of 128940840 in words is "one hundred twenty-eight million, nine hundred forty thousand, eight hundred forty".