20561420244 has 12 divisors (see below), whose sum is σ = 47976647264. Its totient is φ = 6853806744.

The previous prime is 20561420237. The next prime is 20561420261. The reversal of 20561420244 is 44202416502.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 856725832 + ... + 856725855.

Almost surely, 2^20561420244 is an apocalyptic number.

It is an amenable number.

20561420244 is an abundant number, since it is smaller than the sum of its proper divisors (27415227020).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20561420244 is a wasteful number, since it uses less digits than its factorization.

20561420244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1713451694 (or 1713451692 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 30.

Adding to 20561420244 its reverse (44202416502), we get a palindrome (64763836746).

The spelling of 20561420244 in words is "twenty billion, five hundred sixty-one million, four hundred twenty thousand, two hundred forty-four".