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81089 = 131619
BaseRepresentation
bin10011110011000001
311010020022
4103303001
510043324
61423225
7455261
oct236301
9133208
1081089
1155a18
123ab15
132aba8
14217a1
151905e
hex13cc1

81089 has 4 divisors (see below), whose sum is σ = 81840. Its totient is φ = 80340.

The previous prime is 81083. The next prime is 81097. The reversal of 81089 is 98018.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 98018 = 249009.

It is a cyclic number.

It is not a de Polignac number, because 81089 - 28 = 80833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81083) 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, 179 + ... + 440.

It is an arithmetic number, because the mean of its divisors is an integer number (20460).

281089 is an apocalyptic number.

It is an amenable number.

81089 is a deficient number, since it is larger than the sum of its proper divisors (751).

81089 is a wasteful number, since it uses less digits than its factorization.

81089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 750.

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 81089 is about 284.7613035509. The cubic root of 81089 is about 43.2833282485.

The spelling of 81089 in words is "eighty-one thousand, eighty-nine".

Divisors: 1 131 619 81089