561001220 has 144 divisors (see below), whose sum is σ = 1380012480. Its totient is φ = 190294272.

The previous prime is 561001171. The next prime is 561001247. The reversal of 561001220 is 22100165.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4035911 + ... + 4036049.

It is an arithmetic number, because the mean of its divisors is an integer number (9583420).

Almost surely, 2^561001220 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 561001220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (690006240).

561001220 is an abundant number, since it is smaller than the sum of its proper divisors (819011260).

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

561001220 is a wasteful number, since it uses less digits than its factorization.

561001220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242 (or 221 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 561001220 is about 23685.4643188602. The cubic root of 561001220 is about 824.7479952679.

Adding to 561001220 its reverse (22100165), we get a palindrome (583101385).

The spelling of 561001220 in words is "five hundred sixty-one million, one thousand, two hundred twenty".