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81131 is a prime number
BaseRepresentation
bin10011110011101011
311010021212
4103303223
510044011
61423335
7455351
oct236353
9133255
1081131
1155a56
123ab4b
132ac0b
14217d1
151908b
hex13ceb

81131 has 2 divisors, whose sum is σ = 81132. Its totient is φ = 81130.

The previous prime is 81119. The next prime is 81157. The reversal of 81131 is 13118.

Added to its reverse (13118) it gives a square (94249 = 3072).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81131 - 210 = 80107 is a prime.

It is a super-2 number, since 2×811312 = 13164478322, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (81101) 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 as a sum of consecutive naturals, namely, 40565 + 40566.

It is an arithmetic number, because the mean of its divisors is an integer number (40566).

281131 is an apocalyptic number.

81131 is a deficient number, since it is larger than the sum of its proper divisors (1).

81131 is an equidigital number, since it uses as much as digits as its factorization.

81131 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24, while the sum is 14.

The square root of 81131 is about 284.8350399793. The cubic root of 81131 is about 43.2907998168.

Adding to 81131 its reverse (13118), we get a palindrome (94249).

It can be divided in two parts, 81 and 131, that added together give a palindrome (212).

The spelling of 81131 in words is "eighty-one thousand, one hundred thirty-one".