128137856 has 64 divisors (see below), whose sum is σ = 318288960. Its totient is φ = 49920000.

The previous prime is 128137831. The next prime is 128137859. The reversal of 128137856 is 658731821.

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (128137859) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3356 + ... + 16356.

It is an arithmetic number, because the mean of its divisors is an integer number (4973265).

Almost surely, 2^128137856 is an apocalyptic number.

128137856 is a gapful number since it is divisible by the number (16) 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 128137856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159144480).

128137856 is an abundant number, since it is smaller than the sum of its proper divisors (190151104).

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

128137856 is a wasteful number, since it uses less digits than its factorization.

128137856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13033 (or 13021 counting only the distinct ones).

The product of its digits is 80640, while the sum is 41.

The square root of 128137856 is about 11319.7992915069. The cubic root of 128137856 is about 504.1492797076.

The spelling of 128137856 in words is "one hundred twenty-eight million, one hundred thirty-seven thousand, eight hundred fifty-six".