128111688 has 24 divisors (see below), whose sum is σ = 346969350. Its totient is φ = 42703872.

The previous prime is 128111639. The next prime is 128111689. The reversal of 128111688 is 886111821.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 104898564 + 23213124 = 10242^2 + 4818^2 .

It is a tau number, because it is divible by the number of its divisors (24).

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

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (128111689) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 889593 + ... + 889736.

Almost surely, 2^128111688 is an apocalyptic number.

128111688 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

128111688 is an abundant number, since it is smaller than the sum of its proper divisors (218857662).

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

128111688 is a wasteful number, since it uses less digits than its factorization.

128111688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1779341 (or 1779334 counting only the distinct ones).

The product of its digits is 6144, while the sum is 36.

The square root of 128111688 is about 11318.6433816072. The cubic root of 128111688 is about 504.1149586596.

The spelling of 128111688 in words is "one hundred twenty-eight million, one hundred eleven thousand, six hundred eighty-eight".