8561220 has 48 divisors (see below), whose sum is σ = 24235008. Its totient is φ = 2257920.

The previous prime is 8561213. The next prime is 8561237. The reversal of 8561220 is 221658.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5085 + ... + 6555.

It is an arithmetic number, because the mean of its divisors is an integer number (504896).

Almost surely, 2^8561220 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 8561220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12117504).

8561220 is an abundant number, since it is smaller than the sum of its proper divisors (15673788).

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

8561220 is a wasteful number, since it uses less digits than its factorization.

8561220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1580 (or 1578 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 8561220 is about 2925.9562539450. The cubic root of 8561220 is about 204.5715421721.

Adding to 8561220 its reverse (221658), we get a palindrome (8782878).

The spelling of 8561220 in words is "eight million, five hundred sixty-one thousand, two hundred twenty".