10561 has 4 divisors (see below), whose sum is σ = 10800. Its totient is φ = 10324.

The previous prime is 10559. The next prime is 10567. The reversal of 10561 is 16501.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16501 = 29 ⋅569.

It is a cyclic number.

It is not a de Polignac number, because 10561 - 2¹ = 10559 is a prime.

It is a super-2 number, since 2×10561² = 223069442, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (10567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31 + ... + 148.

It is an arithmetic number, because the mean of its divisors is an integer number (2700).

2¹⁰⁵⁶¹ is an apocalyptic number.

It is an amenable number.

10561 is a deficient number, since it is larger than the sum of its proper divisors (239).

10561 is an equidigital number, since it uses as much as digits as its factorization.

10561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238.

The product of its (nonzero) digits is 30, while the sum is 13.

The square root of 10561 is about 102.7667261325. The cubic root of 10561 is about 21.9399187140.

The spelling of 10561 in words is "ten thousand, five hundred sixty-one".