81128 has 8 divisors (see below), whose sum is σ = 152130. Its totient is φ = 40560.
The previous prime is 81119. The next prime is 81131. The reversal of 81128 is 82118.
It can be written as a sum of positive squares in only one way, i.e., 77284 + 3844 = 278^2 + 62^2 .
It is a tau number, because it is divible by the number of its divisors (8).
It is a nude number because it is divisible by every one of its digits.
It is an unprimeable number.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5063 + ... + 5078.
281128 is an apocalyptic number.
It is an amenable number.
81128 is a deficient number, since it is larger than the sum of its proper divisors (71002).
81128 is a wasteful number, since it uses less digits than its factorization.
81128 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 10147 (or 10143 counting only the distinct ones).
The product of its digits is 128, while the sum is 20.
The square root of 81128 is about 284.8297737246. The cubic root of 81128 is about 43.2902662189.
Subtracting 81128 from its reverse (82118), we obtain a triangular number (990 = T44).
The spelling of 81128 in words is "eighty-one thousand, one hundred twenty-eight".
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