81133 has 6 divisors (see below), whose sum is σ = 88494. Its totient is φ = 73944.
The previous prime is 81131. The next prime is 81157. The reversal of 81133 is 33118.
It can be written as a sum of positive squares in only one way, i.e., 56169 + 24964 = 237^2 + 158^2 .
It is not a de Polignac number, because 81133 - 21 = 81131 is a prime.
It is a Duffinian number.
81133 is a lucky number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (81131) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 988 + ... + 1066.
It is an arithmetic number, because the mean of its divisors is an integer number (14749).
281133 is an apocalyptic number.
It is an amenable number.
81133 is a deficient number, since it is larger than the sum of its proper divisors (7361).
81133 is an equidigital number, since it uses as much as digits as its factorization.
81133 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 171 (or 92 counting only the distinct ones).
The product of its digits is 72, while the sum is 16.
The square root of 81133 is about 284.8385507617. The cubic root of 81133 is about 43.2911555415.
The spelling of 81133 in words is "eighty-one thousand, one hundred thirty-three".
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