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81984 = 263761
BaseRepresentation
bin10100000001000000
311011110110
4110001000
510110414
61431320
7461010
oct240100
9134413
1081984
1156661
123b540
132b416
1421c40
1519459
hex14040

81984 has 56 divisors (see below), whose sum is σ = 251968. Its totient is φ = 23040.

The previous prime is 81973. The next prime is 82003. The reversal of 81984 is 48918.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (56).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1314 + ... + 1374.

281984 is an apocalyptic number.

81984 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125984).

81984 is an abundant number, since it is smaller than the sum of its proper divisors (169984).

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

81984 is a wasteful number, since it uses less digits than its factorization.

81984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83 (or 73 counting only the distinct ones).

The product of its digits is 2304, while the sum is 30.

The square root of 81984 is about 286.3284826908. The cubic root of 81984 is about 43.4419889949.

It can be divided in two parts, 819 and 84, that added together give a triangular number (903 = T42).

The spelling of 81984 in words is "eighty-one thousand, nine hundred eighty-four".

Divisors: 1 2 3 4 6 7 8 12 14 16 21 24 28 32 42 48 56 61 64 84 96 112 122 168 183 192 224 244 336 366 427 448 488 672 732 854 976 1281 1344 1464 1708 1952 2562 2928 3416 3904 5124 5856 6832 10248 11712 13664 20496 27328 40992 81984