2561720 has 48 divisors (see below), whose sum is σ = 6710040. Its totient is φ = 877632.

The previous prime is 2561683. The next prime is 2561723. The reversal of 2561720 is 271652.

2561720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2561723) by changing a digit.

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, 1307 + ... + 2613.

2^2561720 is an apocalyptic number.

2561720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

2561720 is the 1307-th pentagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2561720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3355020).

2561720 is an abundant number, since it is smaller than the sum of its proper divisors (4148320).

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

2561720 is a wasteful number, since it uses less digits than its factorization.

2561720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1332 (or 1321 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 2561720 is about 1600.5374097471. The cubic root of 2561720 is about 136.8287059443.

The spelling of 2561720 in words is "two million, five hundred sixty-one thousand, seven hundred twenty".