561905 has 8 divisors (see below), whose sum is σ = 690984. Its totient is φ = 438400.

The previous prime is 561839. The next prime is 561907. The reversal of 561905 is 509165.

It can be written as a sum of positive squares in 4 ways, for example, as 2401 + 559504 = 49^2 + 748^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 561905 - 2¹⁴ = 545521 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561907) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1166 + ... + 1575.

It is an arithmetic number, because the mean of its divisors is an integer number (86373).

2⁵⁶¹⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

561905 is a deficient number, since it is larger than the sum of its proper divisors (129079).

561905 is a wasteful number, since it uses less digits than its factorization.

561905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2787.

The product of its (nonzero) digits is 1350, while the sum is 26.

The square root of 561905 is about 749.6032283815. The cubic root of 561905 is about 82.5190650766.

It can be divided in two parts, 561 and 905, that multiplied together give a palindrome (507705).

The spelling of 561905 in words is "five hundred sixty-one thousand, nine hundred five".