561644636 has 96 divisors (see below), whose sum is σ = 1245404160. Its totient is φ = 216082944.

The previous prime is 561644599. The next prime is 561644669. The reversal of 561644636 is 636446165.

It is a junction number, because it is equal to n+sod(n) for n = 561644593 and 561644602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2410376 + ... + 2410608.

It is an arithmetic number, because the mean of its divisors is an integer number (12972960).

Almost surely, 2^561644636 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 561644636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (622702080).

561644636 is an abundant number, since it is smaller than the sum of its proper divisors (683759524).

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

561644636 is a wasteful number, since it uses less digits than its factorization.

561644636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 483 (or 481 counting only the distinct ones).

The product of its digits is 311040, while the sum is 41.

The square root of 561644636 is about 23699.0429342621. The cubic root of 561644636 is about 825.0631777758.

The spelling of 561644636 in words is "five hundred sixty-one million, six hundred forty-four thousand, six hundred thirty-six".