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128988 = 22323583
BaseRepresentation
bin11111011111011100
320112221100
4133133130
513111423
62433100
71045026
oct373734
9215840
10128988
1188a02
1262790
1346932
1435016
1528343
hex1f7dc

128988 has 18 divisors (see below), whose sum is σ = 326144. Its totient is φ = 42984.

The previous prime is 128987. The next prime is 128993. The reversal of 128988 is 889821.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 3583 = 128988 / (1 + 2 + 8 + 9 + 8 + 8).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1756 + ... + 1827.

2128988 is an apocalyptic number.

128988 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

128988 is an abundant number, since it is smaller than the sum of its proper divisors (197156).

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

128988 is a wasteful number, since it uses less digits than its factorization.

128988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3593 (or 3588 counting only the distinct ones).

The product of its digits is 9216, while the sum is 36.

The square root of 128988 is about 359.1489941515. The cubic root of 128988 is about 50.5261766718.

The spelling of 128988 in words is "one hundred twenty-eight thousand, nine hundred eighty-eight".

Divisors: 1 2 3 4 6 9 12 18 36 3583 7166 10749 14332 21498 32247 42996 64494 128988