2561660 has 24 divisors (see below), whose sum is σ = 5409600. Its totient is φ = 1018944.

The previous prime is 2561659. The next prime is 2561681. The reversal of 2561660 is 661652.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6797 + ... + 7163.

It is an arithmetic number, because the mean of its divisors is an integer number (225400).

2^2561660 is an apocalyptic number.

2561660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2561660 is an abundant number, since it is smaller than the sum of its proper divisors (2847940).

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

2561660 is a wasteful number, since it uses less digits than its factorization.

2561660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 725 (or 723 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 2561660 is about 1600.5186659330. The cubic root of 2561660 is about 136.8276376794.

The spelling of 2561660 in words is "two million, five hundred sixty-one thousand, six hundred sixty".