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87840 = 2532561
BaseRepresentation
bin10101011100100000
311110111100
4111130200
510302330
61514400
7514044
oct253440
9143440
1087840
115aaa5
1242a00
1330c9c
1424024
151b060
hex15720

87840 has 72 divisors (see below), whose sum is σ = 304668. Its totient is φ = 23040.

The previous prime is 87833. The next prime is 87853. The reversal of 87840 is 4878.

It is a happy number.

87840 is nontrivially palindromic in base 11.

It can be written as a sum of positive squares in 2 ways, for example, as 76176 + 11664 = 276^2 + 108^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1410 + ... + 1470.

287840 is an apocalyptic number.

87840 is a gapful number since it is divisible by the number (80) 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 87840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (152334).

87840 is an abundant number, since it is smaller than the sum of its proper divisors (216828).

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

87840 is a wasteful number, since it uses less digits than its factorization.

87840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82 (or 71 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 87840 is about 296.3781368455. The cubic root of 87840 is about 44.4526281227.

The spelling of 87840 in words is "eighty-seven thousand, eight hundred forty".