561611 has 4 divisors (see below), whose sum is σ = 568800. Its totient is φ = 554424.

The previous prime is 561607. The next prime is 561667. The reversal of 561611 is 116165.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 561611 - 2² = 561607 is a prime.

It is not an unprimeable number, because it can be changed into a prime (531611) 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, 3476 + ... + 3633.

It is an arithmetic number, because the mean of its divisors is an integer number (142200).

2⁵⁶¹⁶¹¹ is an apocalyptic number.

561611 is a deficient number, since it is larger than the sum of its proper divisors (7189).

561611 is an equidigital number, since it uses as much as digits as its factorization.

561611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7188.

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

The square root of 561611 is about 749.4070989789. The cubic root of 561611 is about 82.5046706875.

Adding to 561611 its reverse (116165), we get a palindrome (677776).

It can be divided in two parts, 5616 and 11, that multiplied together give a triangular number (61776 = T₃₅₁).

The spelling of 561611 in words is "five hundred sixty-one thousand, six hundred eleven".