20105508131172 has 36 divisors (see below), whose sum is σ = 50823158742720. Its totient is φ = 6701717088432.

The previous prime is 20105508131167. The next prime is 20105508131173. The reversal of 20105508131172 is 27113180550102.

20105508131172 is a `hidden beast` number, since 2 + 0 + 1 + 0 + 5 + 508 + 131 + 17 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (20105508131173) 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, 2888272 + ... + 6968007.

It is an arithmetic number, because the mean of its divisors is an integer number (1411754409520).

Almost surely, 2^{20105508131172} is an apocalyptic number.

It is an amenable number.

20105508131172 is an abundant number, since it is smaller than the sum of its proper divisors (30717650611548).

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

20105508131172 is a wasteful number, since it uses less digits than its factorization.

20105508131172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9912952 (or 9912947 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 36.

Adding to 20105508131172 its reverse (27113180550102), we get a palindrome (47218688681274).

The spelling of 20105508131172 in words is "twenty trillion, one hundred five billion, five hundred eight million, one hundred thirty-one thousand, one hundred seventy-two".