20561705020 has 24 divisors (see below), whose sum is σ = 45719556624. Its totient is φ = 7740877056.

The previous prime is 20561705011. The next prime is 20561705053. The reversal of 20561705020 is 2050716502.

It is a self number, because there is not a number n which added to its sum of digits gives 20561705020.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30237462 + ... + 30238141.

It is an arithmetic number, because the mean of its divisors is an integer number (1904981526).

Almost surely, 2^20561705020 is an apocalyptic number.

20561705020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20561705020 is an abundant number, since it is smaller than the sum of its proper divisors (25157851604).

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

20561705020 is a wasteful number, since it uses less digits than its factorization.

20561705020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60475629 (or 60475627 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 28.

The spelling of 20561705020 in words is "twenty billion, five hundred sixty-one million, seven hundred five thousand, twenty".