21631517421171 has 16 divisors (see below), whose sum is σ = 32965737936384. Its totient is φ = 12359582469504.

The previous prime is 21631517421139. The next prime is 21631517421181. The reversal of 21631517421171 is 17112471513612.

It is not a de Polignac number, because 21631517421171 - 2⁵ = 21631517421139 is a prime.

It is a super-2 number, since 2×21631517421171² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21631517421181) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53319286 + ... + 53723451.

It is an arithmetic number, because the mean of its divisors is an integer number (2060358621024).

Almost surely, 2^{21631517421171} is an apocalyptic number.

21631517421171 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21631517421171 is a deficient number, since it is larger than the sum of its proper divisors (11334220515213).

21631517421171 is a wasteful number, since it uses less digits than its factorization.

21631517421171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107052370.

The product of its digits is 70560, while the sum is 42.

Adding to 21631517421171 its reverse (17112471513612), we get a palindrome (38743988934783).

The spelling of 21631517421171 in words is "twenty-one trillion, six hundred thirty-one billion, five hundred seventeen million, four hundred twenty-one thousand, one hundred seventy-one".