20561212842 has 8 divisors (see below), whose sum is σ = 41122425696. Its totient is φ = 6853737612.

The previous prime is 20561212829. The next prime is 20561212849. The reversal of 20561212842 is 24821216502.

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

20561212842 is an admirable number.

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 3 ways as a sum of consecutive naturals, for example, 1713434398 + ... + 1713434409.

It is an arithmetic number, because the mean of its divisors is an integer number (5140303212).

Almost surely, 2^20561212842 is an apocalyptic number.

20561212842 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

20561212842 is a wasteful number, since it uses less digits than its factorization.

20561212842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3426868812.

The product of its (nonzero) digits is 15360, while the sum is 33.

The spelling of 20561212842 in words is "twenty billion, five hundred sixty-one million, two hundred twelve thousand, eight hundred forty-two".