561904 has 40 divisors (see below), whose sum is σ = 1294560. Its totient is φ = 231168.

The previous prime is 561839. The next prime is 561907. The reversal of 561904 is 409165.

It is a super-2 number, since 2×561904² = 631472210432, which contains 22 as substring.

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, 3162 + ... + 3334.

It is an arithmetic number, because the mean of its divisors is an integer number (32364).

2⁵⁶¹⁹⁰⁴ 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 561904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (647280).

561904 is an abundant number, since it is smaller than the sum of its proper divisors (732656).

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

561904 is a wasteful number, since it uses less digits than its factorization.

561904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217 (or 211 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 561904 is about 749.6025613617. The cubic root of 561904 is about 82.5190161246.

The spelling of 561904 in words is "five hundred sixty-one thousand, nine hundred four".