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81081 = 3471113
BaseRepresentation
bin10011110010111001
311010020000
4103302321
510043311
61423213
7455250
oct236271
9133200
1081081
1155a10
123ab09
132aba0
1421797
1519056
hex13cb9

81081 has 40 divisors (see below), whose sum is σ = 162624. Its totient is φ = 38880.

The previous prime is 81077. The next prime is 81083. The reversal of 81081 is 18018.

It is a happy number.

It is not a de Polignac number, because 81081 - 22 = 81077 is a prime.

It is a super-2 number, since 2×810812 = 13148257122, which contains 22 as substring.

81081 is a lucky 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 39 ways as a sum of consecutive naturals, for example, 6231 + ... + 6243.

281081 is an apocalyptic number.

81081 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

81081 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81312).

81081 is a wasteful number, since it uses less digits than its factorization.

81081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43 (or 34 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 81081 is about 284.7472563520. The cubic root of 81081 is about 43.2819048001.

Adding to 81081 its reverse (18018), we get a palindrome (99099).

It can be divided in two parts, 8 and 1081, that added together give a square (1089 = 332).

The spelling of 81081 in words is "eighty-one thousand, eighty-one".