20117635723521 has 12 divisors (see below), whose sum is σ = 33210065321472. Its totient is φ = 11495791841976.

The previous prime is 20117635723519. The next prime is 20117635723643. The reversal of 20117635723521 is 12532753671102.

20117635723521 is a `hidden beast` number, since 2 + 0 + 1 + 1 + 7 + 635 + 7 + 2 + 3 + 5 + 2 + 1 = 666.

It is not a de Polignac number, because 20117635723521 - 2¹ = 20117635723519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20117635723321) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 159663775521 + ... + 159663775646.

It is an arithmetic number, because the mean of its divisors is an integer number (2767505443456).

Almost surely, 2^{20117635723521} is an apocalyptic number.

20117635723521 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20117635723521 is a deficient number, since it is larger than the sum of its proper divisors (13092429597951).

20117635723521 is a wasteful number, since it uses less digits than its factorization.

20117635723521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319327551180 (or 319327551177 counting only the distinct ones).

The product of its (nonzero) digits is 529200, while the sum is 45.

The spelling of 20117635723521 in words is "twenty trillion, one hundred seventeen billion, six hundred thirty-five million, seven hundred twenty-three thousand, five hundred twenty-one".