20561212798 has 32 divisors (see below), whose sum is σ = 36259671744. Its totient is φ = 8559758592.

The previous prime is 20561212787. The next prime is 20561212829. The reversal of 20561212798 is 89721216502.

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 15 ways as a sum of consecutive naturals, for example, 287440 + ... + 351772.

It is an arithmetic number, because the mean of its divisors is an integer number (1133114742).

Almost surely, 2^20561212798 is an apocalyptic number.

20561212798 is a deficient number, since it is larger than the sum of its proper divisors (15698458946).

20561212798 is a wasteful number, since it uses less digits than its factorization.

20561212798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64996.

The product of its (nonzero) digits is 120960, while the sum is 43.

The spelling of 20561212798 in words is "twenty billion, five hundred sixty-one million, two hundred twelve thousand, seven hundred ninety-eight".