20561212841 has 16 divisors (see below), whose sum is σ = 22315068048. Its totient is φ = 18832435200.

The previous prime is 20561212829. The next prime is 20561212849. The reversal of 20561212841 is 14821216502.

It can be written as a sum of positive squares in 8 ways, for example, as 294843241 + 20266369600 = 17171^2 + 142360^2 .

It is a cyclic number.

It is not a de Polignac number, because 20561212841 - 2¹⁴ = 20561196457 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20561212798 and 20561212807.

It is not an unprimeable number, because it can be changed into a prime (20561212849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1065761 + ... + 1084881.

It is an arithmetic number, because the mean of its divisors is an integer number (1394691753).

Almost surely, 2^20561212841 is an apocalyptic number.

It is an amenable number.

20561212841 is a deficient number, since it is larger than the sum of its proper divisors (1753855207).

20561212841 is a wasteful number, since it uses less digits than its factorization.

20561212841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19772.

The product of its (nonzero) digits is 7680, while the sum is 32.

The spelling of 20561212841 in words is "twenty billion, five hundred sixty-one million, two hundred twelve thousand, eight hundred forty-one".