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81144 = 23327223
BaseRepresentation
bin10011110011111000
311010022100
4103303320
510044034
61423400
7455400
oct236370
9133270
1081144
1155a68
123ab60
132ac1b
1421800
1519099
hex13cf8

81144 has 72 divisors (see below), whose sum is σ = 266760. Its totient is φ = 22176.

The previous prime is 81131. The next prime is 81157. The reversal of 81144 is 44118.

It is an interprime number because it is at equal distance from previous prime (81131) and next prime (81157).

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81144.

It is an unprimeable number.

81144 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 3517 + ... + 3539.

It is an arithmetic number, because the mean of its divisors is an integer number (3705).

281144 is an apocalyptic number.

81144 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 81144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133380).

81144 is an abundant number, since it is smaller than the sum of its proper divisors (185616).

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

81144 is a wasteful number, since it uses less digits than its factorization.

81144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49 (or 35 counting only the distinct ones).

The product of its digits is 128, while the sum is 18.

The square root of 81144 is about 284.8578592913. The cubic root of 81144 is about 43.2931119225.

It can be divided in two parts, 8114 and 4, that added together give a palindrome (8118).

The spelling of 81144 in words is "eighty-one thousand, one hundred forty-four".

Divisors: 1 2 3 4 6 7 8 9 12 14 18 21 23 24 28 36 42 46 49 56 63 69 72 84 92 98 126 138 147 161 168 184 196 207 252 276 294 322 392 414 441 483 504 552 588 644 828 882 966 1127 1176 1288 1449 1656 1764 1932 2254 2898 3381 3528 3864 4508 5796 6762 9016 10143 11592 13524 20286 27048 40572 81144