561561 has 48 divisors (see below), whose sum is σ = 1072512. Its totient is φ = 253440.

The previous prime is 561559. The next prime is 561599. The reversal of 561561 is 165165.

561561 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 561561 - 2¹ = 561559 is a prime.

It is a hoax number, since the sum of its digits (24) coincides with the sum of the digits of its distinct prime factors.

561561 is strictly pandigital in base 7.

561561 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561521) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 33025 + ... + 33041.

It is an arithmetic number, because the mean of its divisors is an integer number (22344).

2⁵⁶¹⁵⁶¹ is an apocalyptic number.

561561 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

It is an amenable number.

561561 is a deficient number, since it is larger than the sum of its proper divisors (510951).

561561 is a wasteful number, since it uses less digits than its factorization.

561561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62 (or 51 counting only the distinct ones).

The product of its digits is 900, while the sum is 24.

The square root of 561561 is about 749.3737385310. The cubic root of 561561 is about 82.5022221624.

The spelling of 561561 in words is "five hundred sixty-one thousand, five hundred sixty-one".