9561 has 4 divisors (see below), whose sum is σ = 12752. Its totient is φ = 6372.

The previous prime is 9551. The next prime is 9587. The reversal of 9561 is 1659.

9561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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.

It is not a de Polignac number, because 9561 - 2⁶ = 9497 is a prime.

It is a D-number.

It is a Duffinian number.

9561 is a lucky number.

It is a plaindrome in base 14 and base 16.

It is not an unprimeable number, because it can be changed into a prime (9511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1591 + ... + 1596.

It is an arithmetic number, because the mean of its divisors is an integer number (3188).

2⁹⁵⁶¹ is an apocalyptic number.

It is an amenable number.

9561 is a deficient number, since it is larger than the sum of its proper divisors (3191).

9561 is a wasteful number, since it uses less digits than its factorization.

9561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3190.

The product of its digits is 270, while the sum is 21.

The square root of 9561 is about 97.7803661274. The cubic root of 9561 is about 21.2243519858.

The spelling of 9561 in words is "nine thousand, five hundred sixty-one".