116561 has 4 divisors (see below), whose sum is σ = 117300. Its totient is φ = 115824.

The previous prime is 116549. The next prime is 116579. The reversal of 116561 is 165611.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 102400 + 14161 = 320^2 + 119^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-116561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (116531) 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, 26 + ... + 483.

It is an arithmetic number, because the mean of its divisors is an integer number (29325).

2¹¹⁶⁵⁶¹ is an apocalyptic number.

It is an amenable number.

116561 is a deficient number, since it is larger than the sum of its proper divisors (739).

116561 is an equidigital number, since it uses as much as digits as its factorization.

116561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 738.

The product of its digits is 180, while the sum is 20.

The square root of 116561 is about 341.4103103305. The cubic root of 116561 is about 48.8484837951.

The spelling of 116561 in words is "one hundred sixteen thousand, five hundred sixty-one".