2781440 has 72 divisors (see below), whose sum is σ = 6953688. Its totient is φ = 1064960.

The previous prime is 2781433. The next prime is 2781451. The reversal of 2781440 is 441872.

It can be written as a sum of positive squares in 4 ways, for example, as 65536 + 2715904 = 256^2 + 1648^2 .

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 7 ways as a sum of consecutive naturals, for example, 52454 + ... + 52506.

It is an arithmetic number, because the mean of its divisors is an integer number (96579).

2^2781440 is an apocalyptic number.

2781440 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 2781440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3476844).

2781440 is an abundant number, since it is smaller than the sum of its proper divisors (4172248).

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

2781440 is an equidigital number, since it uses as much as digits as its factorization.

2781440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 2781440 is about 1667.7649714513. The cubic root of 2781440 is about 140.6338605117.

The spelling of 2781440 in words is "two million, seven hundred eighty-one thousand, four hundred forty".