2561780 has 48 divisors (see below), whose sum is σ = 5927040. Its totient is φ = 924288.

The previous prime is 2561771. The next prime is 2561807. The reversal of 2561780 is 871652.

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15257 + ... + 15423.

It is an arithmetic number, because the mean of its divisors is an integer number (123480).

2^2561780 is an apocalyptic number.

2561780 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 2561780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2963520).

2561780 is an abundant number, since it is smaller than the sum of its proper divisors (3365260).

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

2561780 is a wasteful number, since it uses less digits than its factorization.

2561780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 248 (or 246 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 2561780 is about 1600.5561533417. The cubic root of 2561780 is about 136.8297741925.

The spelling of 2561780 in words is "two million, five hundred sixty-one thousand, seven hundred eighty".