2840 has 16 divisors (see below), whose sum is σ = 6480. Its totient is φ = 1120.

The previous prime is 2837. The next prime is 2843. The reversal of 2840 is 482.

2840 = 5² + 6² + ... + 20².

It is an interprime number because it is at equal distance from previous prime (2837) and next prime (2843).

It is a plaindrome in base 12.

It is a nialpdrome in base 8 and base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5 + ... + 75.

It is an arithmetic number, because the mean of its divisors is an integer number (405).

2840 is a gapful number since it is divisible by the number (20) 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 2840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3240).

2840 is an abundant number, since it is smaller than the sum of its proper divisors (3640).

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

2840 is a wasteful number, since it uses less digits than its factorization.

2840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82 (or 78 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 2840 is about 53.2916503779. The cubic root of 2840 is about 14.1613975022.

The spelling of 2840 in words is "two thousand, eight hundred forty".