20553563556 has 72 divisors (see below), whose sum is σ = 52901372160. Its totient is φ = 6726661824.

The previous prime is 20553563551. The next prime is 20553563573. The reversal of 20553563556 is 65536535502.

It is a happy number.

20553563556 is a `hidden beast` number, since 2 + 0 + 5 + 5 + 3 + 5 + 635 + 5 + 6 = 666.

It is not an unprimeable number, because it can be changed into a prime (20553563551) 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 23 ways as a sum of consecutive naturals, for example, 1827406 + ... + 1838618.

It is an arithmetic number, because the mean of its divisors is an integer number (734741280).

Almost surely, 2^20553563556 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20553563556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26450686080).

20553563556 is an abundant number, since it is smaller than the sum of its proper divisors (32347808604).

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

20553563556 is a wasteful number, since it uses less digits than its factorization.

20553563556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12145 (or 12140 counting only the distinct ones).

The product of its (nonzero) digits is 2025000, while the sum is 45.

The spelling of 20553563556 in words is "twenty billion, five hundred fifty-three million, five hundred sixty-three thousand, five hundred fifty-six".