561331221 has 24 divisors (see below), whose sum is σ = 851051040. Its totient is φ = 328463520.

The previous prime is 561331219. The next prime is 561331223. The reversal of 561331221 is 122133165.

It is an interprime number because it is at equal distance from previous prime (561331219) and next prime (561331223).

It is not a de Polignac number, because 561331221 - 2¹ = 561331219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 561331191 and 561331200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561331223) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16135 + ... + 37188.

It is an arithmetic number, because the mean of its divisors is an integer number (35460460).

Almost surely, 2^561331221 is an apocalyptic number.

It is an amenable number.

561331221 is a deficient number, since it is larger than the sum of its proper divisors (289719819).

561331221 is a wasteful number, since it uses less digits than its factorization.

561331221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53377 (or 53366 counting only the distinct ones).

The product of its digits is 1080, while the sum is 24.

The square root of 561331221 is about 23692.4296136973. The cubic root of 561331221 is about 824.9096790009.

Adding to 561331221 its reverse (122133165), we get a palindrome (683464386).

The spelling of 561331221 in words is "five hundred sixty-one million, three hundred thirty-one thousand, two hundred twenty-one".