561911 has 4 divisors (see below), whose sum is σ = 642192. Its totient is φ = 481632.

The previous prime is 561907. The next prime is 561917. The reversal of 561911 is 119165.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 119165 = 5 ⋅23833.

It is a cyclic number.

It is not a de Polignac number, because 561911 - 2² = 561907 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40130 + ... + 40143.

It is an arithmetic number, because the mean of its divisors is an integer number (160548).

2⁵⁶¹⁹¹¹ is an apocalyptic number.

561911 is a deficient number, since it is larger than the sum of its proper divisors (80281).

561911 is an equidigital number, since it uses as much as digits as its factorization.

561911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80280.

The product of its digits is 270, while the sum is 23.

The square root of 561911 is about 749.6072304881. The cubic root of 561911 is about 82.5193587873.

It can be divided in two parts, 5 and 61911, that added together give a palindrome (61916).

The spelling of 561911 in words is "five hundred sixty-one thousand, nine hundred eleven".