505561 has 4 divisors (see below), whose sum is σ = 577792. Its totient is φ = 433332.

The previous prime is 505559. The next prime is 505573. The reversal of 505561 is 165505.

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 a cyclic number.

It is not a de Polignac number, because 505561 - 2¹ = 505559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (505501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36105 + ... + 36118.

It is an arithmetic number, because the mean of its divisors is an integer number (144448).

2⁵⁰⁵⁵⁶¹ is an apocalyptic number.

It is an amenable number.

505561 is a deficient number, since it is larger than the sum of its proper divisors (72231).

505561 is an equidigital number, since it uses as much as digits as its factorization.

505561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72230.

The product of its (nonzero) digits is 750, while the sum is 22.

The square root of 505561 is about 711.0281288388. The cubic root of 505561 is about 79.6632196435.

The spelling of 505561 in words is "five hundred five thousand, five hundred sixty-one".