20217807356520 has 64 divisors (see below), whose sum is σ = 61384186221120. Its totient is φ = 5326458481664.

The previous prime is 20217807356503. The next prime is 20217807356531. The reversal of 20217807356520 is 2565370871202.

It is a self number, because there is not a number n which added to its sum of digits gives 20217807356520.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1014940209 + ... + 1014960128.

It is an arithmetic number, because the mean of its divisors is an integer number (959127909705).

Almost surely, 2^{20217807356520} is an apocalyptic number.

20217807356520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20217807356520 is an abundant number, since it is smaller than the sum of its proper divisors (41166378864600).

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

20217807356520 is a wasteful number, since it uses less digits than its factorization.

20217807356520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2029900434 (or 2029900430 counting only the distinct ones).

The product of its (nonzero) digits is 1411200, while the sum is 48.

The spelling of 20217807356520 in words is "twenty trillion, two hundred seventeen billion, eight hundred seven million, three hundred fifty-six thousand, five hundred twenty".