2261561 has 4 divisors (see below), whose sum is σ = 2394612. Its totient is φ = 2128512.

The previous prime is 2261557. The next prime is 2261569. The reversal of 2261561 is 1651622.

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 714025 + 1547536 = 845^2 + 1244^2 .

It is a cyclic number.

It is not a de Polignac number, because 2261561 - 2² = 2261557 is a prime.

It is a super-2 number, since 2×2261561² = 10229316313442, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2261569) 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, 66500 + ... + 66533.

It is an arithmetic number, because the mean of its divisors is an integer number (598653).

2^2261561 is an apocalyptic number.

It is an amenable number.

2261561 is a deficient number, since it is larger than the sum of its proper divisors (133051).

2261561 is a wasteful number, since it uses less digits than its factorization.

2261561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133050.

The product of its digits is 720, while the sum is 23.

The square root of 2261561 is about 1503.8487290948. The cubic root of 2261561 is about 131.2611189371.

The spelling of 2261561 in words is "two million, two hundred sixty-one thousand, five hundred sixty-one".