561611533520 has 80 divisors (see below), whose sum is σ = 1383208375248. Its totient is φ = 211330375680.

The previous prime is 561611533519. The next prime is 561611533559. The reversal of 561611533520 is 25335116165.

It can be written as a sum of positive squares in 8 ways, for example, as 147560466496 + 414051067024 = 384136^2 + 643468^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2815322 + ... + 3008198.

Almost surely, 2^561611533520 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 561611533520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (691604187624).

561611533520 is an abundant number, since it is smaller than the sum of its proper divisors (821596841728).

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

561611533520 is a wasteful number, since it uses less digits than its factorization.

561611533520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195048 (or 195042 counting only the distinct ones).

The product of its (nonzero) digits is 81000, while the sum is 38.

Adding to 561611533520 its reverse (25335116165), we get a palindrome (586946649685).

The spelling of 561611533520 in words is "five hundred sixty-one billion, six hundred eleven million, five hundred thirty-three thousand, five hundred twenty".