2660561 has 4 divisors (see below), whose sum is σ = 2668452. Its totient is φ = 2652672.

The previous prime is 2660557. The next prime is 2660569. The reversal of 2660561 is 1650662.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1113025 + 1547536 = 1055^2 + 1244^2 .

It is a cyclic number.

It is not a de Polignac number, because 2660561 - 2² = 2660557 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2660561.

It is not an unprimeable number, because it can be changed into a prime (2660569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3416 + ... + 4121.

It is an arithmetic number, because the mean of its divisors is an integer number (667113).

2^2660561 is an apocalyptic number.

It is an amenable number.

2660561 is a deficient number, since it is larger than the sum of its proper divisors (7891).

2660561 is an equidigital number, since it uses as much as digits as its factorization.

2660561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7890.

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

The square root of 2660561 is about 1631.1226195477. The cubic root of 2660561 is about 138.5663381719.

The spelling of 2660561 in words is "two million, six hundred sixty thousand, five hundred sixty-one".