2561940 has 72 divisors (see below), whose sum is σ = 7975968. Its totient is φ = 665280.

The previous prime is 2561929. The next prime is 2561953. The reversal of 2561940 is 491652.

2561940 is a `hidden beast` number, since 2 + 5 + 619 + 40 = 666.

2561940 is digitally balanced in base 2 and base 5, because in such bases it contains all the possibile digits an equal number of times.

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 23 ways as a sum of consecutive naturals, for example, 7575 + ... + 7905.

2^2561940 is an apocalyptic number.

2561940 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 2561940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3987984).

2561940 is an abundant number, since it is smaller than the sum of its proper divisors (5414028).

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

2561940 is a wasteful number, since it uses less digits than its factorization.

2561940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 389 (or 384 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 2561940 is about 1600.6061351875. The cubic root of 2561940 is about 136.8326227728.

The spelling of 2561940 in words is "two million, five hundred sixty-one thousand, nine hundred forty".