561601 has 4 divisors (see below), whose sum is σ = 563332.
Its totient is φ = 559872.
The previous prime is 561599. The next prime is 561607. The reversal of 561601 is 106165.
Adding to 561601 its reverse (106165), we get a palindrome (667766).
It is a semiprime because it is the product of two primes.
It can be written as a sum of positive squares in 2 ways, for example, as 360000 + 201601 = 600^2 + 449^2
It is a 3-Lehmer number, since φ(561601) divides (561601-1)3.
It is a cyclic number.
It is not a de Polignac number, because 561601 - 21 = 561599 is a prime.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (561607) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (7) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 216 + ... + 1081.
It is an arithmetic number, because the mean of its divisors is an integer number (140833).
2561601 is an apocalyptic number.
561601 is the 433-rd octagonal number.
It is an amenable number.
561601 is a deficient number, since it is larger than the sum of its proper divisors (1731).
561601 is a wasteful number, since it uses less digits than its factorization.
561601 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1730.
The product of its (nonzero) digits is 180, while the sum is 19.
The square root of 561601 is about 749.4004270082.
The cubic root of 561601 is about 82.5041809941.
The spelling of 561601 in words is "five hundred sixty-one thousand, six hundred one".