2809440 has 72 divisors (see below), whose sum is σ = 9592128. Its totient is φ = 748800.

The previous prime is 2809439. The next prime is 2809451. The reversal of 2809440 is 449082.

2809440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×2809440² = 15785906227200, which contains 22 as substring.

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 465 + ... + 2415.

It is an arithmetic number, because the mean of its divisors is an integer number (133224).

2^2809440 is an apocalyptic number.

2809440 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 2809440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4796064).

2809440 is an abundant number, since it is smaller than the sum of its proper divisors (6782688).

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

2809440 is a wasteful number, since it uses less digits than its factorization.

2809440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1972 (or 1961 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 2809440 is about 1676.1384191051. The cubic root of 2809440 is about 141.1041933952.

It can be divided in two parts, 2809 and 440, that added together give a square (3249 = 57²).

The spelling of 2809440 in words is "two million, eight hundred nine thousand, four hundred forty".