87440 has 20 divisors (see below), whose sum is σ = 203484. Its totient is φ = 34944.

The previous prime is 87433. The next prime is 87443. The reversal of 87440 is 4478.

It can be written as a sum of positive squares in 2 ways, for example, as 65536 + 21904 = 256^2 + 148^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87443) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 467 + ... + 626.

2⁸⁷⁴⁴⁰ is an apocalyptic number.

87440 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

87440 is an abundant number, since it is smaller than the sum of its proper divisors (116044).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101742).

87440 is a wasteful number, since it uses less digits than its factorization.

87440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1106 (or 1100 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 23.

The square root of 87440 is about 295.7025532524. The cubic root of 87440 is about 44.3850502925.

The spelling of 87440 in words is "eighty-seven thousand, four hundred forty".