128891520 has 128 divisors (see below), whose sum is σ = 456552000. Its totient is φ = 34366464.

The previous prime is 128891509. The next prime is 128891537. The reversal of 128891520 is 25198821.

128891520 is a `hidden beast` number, since 128 + 8 + 9 + 1 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×128891520² = 33226047855820800, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13551 + ... + 21009.

Almost surely, 2^128891520 is an apocalyptic number.

128891520 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 128891520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (228276000).

128891520 is an abundant number, since it is smaller than the sum of its proper divisors (327660480).

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

128891520 is an equidigital number, since it uses as much as digits as its factorization.

128891520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7487 (or 7469 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 128891520 is about 11353.0401214829. The cubic root of 128891520 is about 505.1357606439.

The spelling of 128891520 in words is "one hundred twenty-eight million, eight hundred ninety-one thousand, five hundred twenty".