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128881 = 3592
BaseRepresentation
bin11111011101110001
320112210101
4133131301
513111011
62432401
71044514
oct373561
9215711
10128881
1188915
1262701
134687c
1434d7b
15282c1
hex1f771

128881 has 3 divisors (see below), whose sum is σ = 129241. Its totient is φ = 128522.

The previous prime is 128879. The next prime is 128903. The reversal of 128881 is 188821.

128881 = T358 + T359.

The square root of 128881 is 359.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 188821 = 316091.

It is not a de Polignac number, because 128881 - 21 = 128879 is a prime.

It is a super-2 number, since 2×1288812 = 33220624322, which contains 22 as substring.

It is a Duffinian number.

128881 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (128831) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 180 + ... + 538.

2128881 is an apocalyptic number.

128881 is the 359-th square number.

128881 is the 180-th centered octagonal number.

It is an amenable number.

128881 is a deficient number, since it is larger than the sum of its proper divisors (360).

128881 is an frugal number, since it uses more digits than its factorization.

128881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 718 (or 359 counting only the distinct ones).

The product of its digits is 1024, while the sum is 28.

The cubic root of 128881 is about 50.5122017374.

Multiplying 128881 by its product of digits (1024), we get a square (131974144 = 114882).

It can be divided in two parts, 1288 and 81, that added together give a square (1369 = 372).

The spelling of 128881 in words is "one hundred twenty-eight thousand, eight hundred eighty-one".

Divisors: 1 359 128881