2581440 has 56 divisors (see below), whose sum is σ = 8199120. Its totient is φ = 688128.

The previous prime is 2581429. The next prime is 2581441. The reversal of 2581440 is 441852.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 2581440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2581441) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 385 + ... + 2304.

2^2581440 is an apocalyptic number.

2581440 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 2581440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4099560).

2581440 is an abundant number, since it is smaller than the sum of its proper divisors (5617680).

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

2581440 is a wasteful number, since it uses less digits than its factorization.

2581440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2709 (or 2699 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 2581440 is about 1606.6860303121. The cubic root of 2581440 is about 137.1789091726.

The spelling of 2581440 in words is "two million, five hundred eighty-one thousand, four hundred forty".