20561255120 has 40 divisors (see below), whose sum is σ = 54634193664. Its totient is φ = 7049572992.

The previous prime is 20561255087. The next prime is 20561255123. The reversal of 20561255120 is 2155216502.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20561255123) 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 7 ways as a sum of consecutive naturals, for example, 18357704 + ... + 18358823.

Almost surely, 2^20561255120 is an apocalyptic number.

20561255120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20561255120 is an abundant number, since it is smaller than the sum of its proper divisors (34072938544).

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

20561255120 is a wasteful number, since it uses less digits than its factorization.

20561255120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36716547 (or 36716541 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 29.

The spelling of 20561255120 in words is "twenty billion, five hundred sixty-one million, two hundred fifty-five thousand, one hundred twenty".