81229 has 4 divisors (see below), whose sum is σ = 84060. Its totient is φ = 78400.
The previous prime is 81223. The next prime is 81233. The reversal of 81229 is 92218.
It is a semiprime because it is the product of two primes.
It can be written as a sum of positive squares in 2 ways, for example, as 42025 + 39204 = 205^2 + 198^2 .
It is a cyclic number.
It is not a de Polignac number, because 81229 - 25 = 81197 is a prime.
It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (81223) by changing a digit.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1372 + ... + 1429.
It is an arithmetic number, because the mean of its divisors is an integer number (21015).
281229 is an apocalyptic number.
It is an amenable number.
81229 is a deficient number, since it is larger than the sum of its proper divisors (2831).
81229 is a wasteful number, since it uses less digits than its factorization.
81229 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 2830.
The product of its digits is 288, while the sum is 22.
The square root of 81229 is about 285.0070174575. The cubic root of 81229 is about 43.3082234540.
It can be divided in two parts, 812 and 29, that added together give a square (841 = 292).
The spelling of 81229 in words is "eighty-one thousand, two hundred twenty-nine".
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