20561607221 has 8 divisors (see below), whose sum is σ = 20603650944. Its totient is φ = 20519604000.

The previous prime is 20561607217. The next prime is 20561607223. The reversal of 20561607221 is 12270616502.

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

It is a cyclic number.

It is not a de Polignac number, because 20561607221 - 2² = 20561607217 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20561607223) 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, 1134785 + ... + 1152761.

It is an arithmetic number, because the mean of its divisors is an integer number (2575456368).

Almost surely, 2^20561607221 is an apocalyptic number.

It is an amenable number.

20561607221 is a deficient number, since it is larger than the sum of its proper divisors (42043723).

20561607221 is a wasteful number, since it uses less digits than its factorization.

20561607221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20251.

The product of its (nonzero) digits is 10080, while the sum is 32.

The spelling of 20561607221 in words is "twenty billion, five hundred sixty-one million, six hundred seven thousand, two hundred twenty-one".