128517840 has 240 divisors, whose sum is σ = 489093696. Its totient is φ = 31104000.

The previous prime is 128517811. The next prime is 128517877. The reversal of 128517840 is 48715821.

It is a tau number, because it is divible by the number of its divisors (240).

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 = 128517795 and 128517804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 213540 + ... + 214140.

Almost surely, 2^128517840 is an apocalyptic number.

128517840 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 128517840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (244546848).

128517840 is an abundant number, since it is smaller than the sum of its proper divisors (360575856).

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

128517840 is a wasteful number, since it uses less digits than its factorization.

128517840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 640 (or 622 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 36.

The square root of 128517840 is about 11336.5709101121. The cubic root of 128517840 is about 504.6471279262.

The spelling of 128517840 in words is "one hundred twenty-eight million, five hundred seventeen thousand, eight hundred forty".