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BaseRepresentation
bin10011110111010001
311010121101
4103313101
510100421
61424401
7456130
oct236721
9133541
1081361
1156145
123b101
132b057
1421917
1519191
hex13dd1

81361 has 8 divisors (see below), whose sum is σ = 95040. Its totient is φ = 68208.

The previous prime is 81359. The next prime is 81371. The reversal of 81361 is 16318.

Adding to 81361 its reverse (16318), we get a palindrome (97679).

It can be divided in two parts, 81 and 361, that multiplied together give a square (29241 = 1712).

81361 = 42 + 52 + ... + 622.

81361 is nontrivially palindromic in base 15.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81361 - 21 = 81359 is a prime.

It is a super-2 number, since 2×813612 = 13239224642, which contains 22 as substring.

It is a Duffinian number.

81361 is an undulating number in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81331) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 315 + ... + 511.

It is an arithmetic number, because the mean of its divisors is an integer number (11880).

281361 is an apocalyptic number.

It is an amenable number.

81361 is a deficient number, since it is larger than the sum of its proper divisors (13679).

81361 is a wasteful number, since it uses less digits than its factorization.

81361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263.

The product of its digits is 144, while the sum is 19.

The square root of 81361 is about 285.2384967006. The cubic root of 81361 is about 43.3316698901.

The spelling of 81361 in words is "eighty-one thousand, three hundred sixty-one".

Divisors: 1 7 59 197 413 1379 11623 81361