2543640 has 128 divisors (see below), whose sum is σ = 8709120. Its totient is φ = 588800.

The previous prime is 2543633. The next prime is 2543641. The reversal of 2543640 is 463452.

2543640 = T₂₂₉ + T₂₃₀ + ... + T₃₀₀.

2543640 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

2543640 is a nontrivial binomial coefficient, being equal to C(2256, 2).

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 2543640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2543641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 54097 + ... + 54143.

It is an arithmetic number, because the mean of its divisors is an integer number (68040).

2^2543640 is an apocalyptic number.

2543640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

2543640 is the 2255-th triangular number and also the 1128-th hexagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2543640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4354560).

2543640 is an abundant number, since it is smaller than the sum of its proper divisors (6165480).

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

2543640 is a wasteful number, since it uses less digits than its factorization.

2543640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113 (or 109 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 24.

The square root of 2543640 is about 1594.8793057783. The cubic root of 2543640 is about 136.5060443593.

The spelling of 2543640 in words is "two million, five hundred forty-three thousand, six hundred forty".