21127111172 has 12 divisors (see below), whose sum is σ = 37311642060. Its totient is φ = 10466642016.

The previous prime is 21127111171. The next prime is 21127111189. The reversal of 21127111172 is 27111172112.

It can be written as a sum of positive squares in 2 ways, for example, as 19325448256 + 1801662916 = 139016^2 + 42446^2 .

It is not an unprimeable number, because it can be changed into a prime (21127111171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24227903 + ... + 24228774.

It is an arithmetic number, because the mean of its divisors is an integer number (3109303505).

Almost surely, 2^21127111172 is an apocalyptic number.

It is an amenable number.

21127111172 is a deficient number, since it is larger than the sum of its proper divisors (16184530888).

21127111172 is a wasteful number, since it uses less digits than its factorization.

21127111172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48456790 (or 48456788 counting only the distinct ones).

The product of its digits is 392, while the sum is 26.

Adding to 21127111172 its reverse (27111172112), we get a palindrome (48238283284).

The spelling of 21127111172 in words is "twenty-one billion, one hundred twenty-seven million, one hundred eleven thousand, one hundred seventy-two".