20565697874172 has 96 divisors (see below), whose sum is σ = 53498691800064. Its totient is φ = 6095345184000.

The previous prime is 20565697874159. The next prime is 20565697874179. The reversal of 20565697874172 is 27147879656502.

It is a junction number, because it is equal to n+sod(n) for n = 20565697874097 and 20565697874106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20565697874179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8152422 + ... + 10372722.

It is an arithmetic number, because the mean of its divisors is an integer number (557278039584).

Almost surely, 2^{20565697874172} is an apocalyptic number.

20565697874172 is a gapful number since it is divisible by the number (22) 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 20565697874172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26749345900032).

20565697874172 is an abundant number, since it is smaller than the sum of its proper divisors (32932993925892).

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

20565697874172 is a wasteful number, since it uses less digits than its factorization.

20565697874172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2221859 (or 2221857 counting only the distinct ones).

The product of its (nonzero) digits is 355622400, while the sum is 69.

The spelling of 20565697874172 in words is "twenty trillion, five hundred sixty-five billion, six hundred ninety-seven million, eight hundred seventy-four thousand, one hundred seventy-two".