61561221 has 8 divisors (see below), whose sum is σ = 82159584. Its totient is φ = 41001840.

The previous prime is 61561219. The next prime is 61561231. The reversal of 61561221 is 12216516.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 61561221 - 2¹ = 61561219 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 61561191 and 61561200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61561231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5835 + ... + 12536.

It is an arithmetic number, because the mean of its divisors is an integer number (10269948).

Almost surely, 2^61561221 is an apocalyptic number.

It is an amenable number.

61561221 is a deficient number, since it is larger than the sum of its proper divisors (20598363).

61561221 is a wasteful number, since it uses less digits than its factorization.

61561221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19491.

The product of its digits is 720, while the sum is 24.

The square root of 61561221 is about 7846.0959081571. The cubic root of 61561221 is about 394.8532724271.

Adding to 61561221 its reverse (12216516), we get a palindrome (73777737).

The spelling of 61561221 in words is "sixty-one million, five hundred sixty-one thousand, two hundred twenty-one".