561808 has 40 divisors (see below), whose sum is σ = 1220408. Its totient is φ = 248832.

The previous prime is 561797. The next prime is 561809. The reversal of 561808 is 808165.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 110224 + 451584 = 332^2 + 672^2 .

It is not an unprimeable number, because it can be changed into a prime (561809) by changing a digit.

561808 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7660 + ... + 7732.

2⁵⁶¹⁸⁰⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 561808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (610204).

561808 is an abundant number, since it is smaller than the sum of its proper divisors (658600).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

561808 is a wasteful number, since it uses less digits than its factorization.

561808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131 (or 125 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 561808 is about 749.5385246937. The cubic root of 561808 is about 82.5143164625.

It can be divided in two parts, 561 and 808, that added together give a square (1369 = 37²).

The spelling of 561808 in words is "five hundred sixty-one thousand, eight hundred eight".