42840 has 96 divisors (see below), whose sum is σ = 168480. Its totient is φ = 9216.

The previous prime is 42839. The next prime is 42841. The reversal of 42840 is 4824.

It is a happy number.

42840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (42839) and next prime (42841).

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

It is an Ulam number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42841) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2512 + ... + 2528.

It is an arithmetic number, because the mean of its divisors is an integer number (1755).

2⁴²⁸⁴⁰ is an apocalyptic number.

42840 is a gapful number since it is divisible by the number (40) 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 42840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84240).

42840 is an abundant number, since it is smaller than the sum of its proper divisors (125640).

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

42840 is a wasteful number, since it uses less digits than its factorization.

42840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41 (or 34 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 42840 is about 206.9782597279. The cubic root of 42840 is about 34.9904735978.

The spelling of 42840 in words is "forty-two thousand, eight hundred forty".