20561022621 has 6 divisors (see below), whose sum is σ = 29699254910. Its totient is φ = 13707348408.

The previous prime is 20561022563. The next prime is 20561022667. The reversal of 20561022621 is 12622016502.

20561022621 is a `hidden beast` number, since 2 + 0 + 5 + 6 + 10 + 22 + 621 = 666.

It can be written as a sum of positive squares in only one way, i.e., 19596920121 + 964102500 = 139989^2 + 31050^2 .

It is not a de Polignac number, because 20561022621 - 2¹¹ = 20561020573 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 (20561032621) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1142279026 + ... + 1142279043.

Almost surely, 2^20561022621 is an apocalyptic number.

It is an amenable number.

20561022621 is a deficient number, since it is larger than the sum of its proper divisors (9138232289).

20561022621 is a wasteful number, since it uses less digits than its factorization.

20561022621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2284558075 (or 2284558072 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The spelling of 20561022621 in words is "twenty billion, five hundred sixty-one million, twenty-two thousand, six hundred twenty-one".