Search a number
BaseRepresentation
bin10011111111011000
311011022121
4103333120
510110010
61431024
7460501
oct237730
9134277
1081880
1156577
123b474
132b366
1421ba8
15193da
hex13fd8

81880 has 32 divisors (see below), whose sum is σ = 194400. Its totient is φ = 30976.

The previous prime is 81869. The next prime is 81883. The reversal of 81880 is 8818.

It can be divided in two parts, 818 and 80, that added together give a palindrome (898).

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81883) by changing a digit.

81880 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 in 7 ways as a sum of consecutive naturals, for example, 876 + ... + 964.

It is an arithmetic number, because the mean of its divisors is an integer number (6075).

281880 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97200).

81880 is an abundant number, since it is smaller than the sum of its proper divisors (112520).

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

81880 is a wasteful number, since it uses less digits than its factorization.

81880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123 (or 119 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 25.

The square root of 81880 is about 286.1468154637. The cubic root of 81880 is about 43.4236119188.

The spelling of 81880 in words is "eighty-one thousand, eight hundred eighty".