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81331 is a prime number
BaseRepresentation
bin10011110110110011
311010120021
4103312303
510100311
61424311
7456055
oct236663
9133507
1081331
1156118
123b097
132b033
14218d5
1519171
hex13db3

81331 has 2 divisors, whose sum is σ = 81332. Its totient is φ = 81330.

The previous prime is 81307. The next prime is 81343. The reversal of 81331 is 13318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81331 - 25 = 81299 is a prime.

It is a super-2 number, since 2×813312 = 13229463122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81371) 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, 40665 + 40666.

It is an arithmetic number, because the mean of its divisors is an integer number (40666).

281331 is an apocalyptic number.

81331 is a deficient number, since it is larger than the sum of its proper divisors (1).

81331 is an equidigital number, since it uses as much as digits as its factorization.

81331 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72, while the sum is 16.

The square root of 81331 is about 285.1859042800. The cubic root of 81331 is about 43.3263433827.

Adding to 81331 its reverse (13318), we get a palindrome (94649).

It can be divided in two parts, 8 and 1331, that multiplied together give a cube (10648 = 223).

The spelling of 81331 in words is "eighty-one thousand, three hundred thirty-one".