128931840 has 144 divisors (see below), whose sum is σ = 447174000. Its totient is φ = 34357248.

The previous prime is 128931827. The next prime is 128931851. The reversal of 128931840 is 48139821.

It is a tau number, because it is divible by the number of its divisors (144).

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 = 128931795 and 128931804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 91461 + ... + 92859.

It is an arithmetic number, because the mean of its divisors is an integer number (3105375).

Almost surely, 2^128931840 is an apocalyptic number.

128931840 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 128931840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (223587000).

128931840 is an abundant number, since it is smaller than the sum of its proper divisors (318242160).

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

128931840 is a wasteful number, since it uses less digits than its factorization.

128931840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1432 (or 1409 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 128931840 is about 11354.8157184518. The cubic root of 128931840 is about 505.1884275441.

The spelling of 128931840 in words is "one hundred twenty-eight million, nine hundred thirty-one thousand, eight hundred forty".