20505560036640 has 384 divisors, whose sum is σ = 78179217596928. Its totient is φ = 4410329333760.

The previous prime is 20505560036617. The next prime is 20505560036641. The reversal of 20505560036640 is 4663006550502.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 20505560036592 and 20505560036601.

It is not an unprimeable number, because it can be changed into a prime (20505560036641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 283107630 + ... + 283180050.

It is an arithmetic number, because the mean of its divisors is an integer number (203591712492).

Almost surely, 2^{20505560036640} is an apocalyptic number.

20505560036640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20505560036640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39089608798464).

20505560036640 is an abundant number, since it is smaller than the sum of its proper divisors (57673657560288).

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

20505560036640 is a wasteful number, since it uses less digits than its factorization.

20505560036640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77420 (or 77412 counting only the distinct ones).

The product of its (nonzero) digits is 648000, while the sum is 42.

The spelling of 20505560036640 in words is "twenty trillion, five hundred five billion, five hundred sixty million, thirty-six thousand, six hundred forty".