21611261212 has 12 divisors (see below), whose sum is σ = 38742139296. Its totient is φ = 10542078560.

The previous prime is 21611261207. The next prime is 21611261213. The reversal of 21611261212 is 21216211612.

It is a super-2 number, since 2×21611261212² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21611261213) 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, 65887828 + ... + 65888155.

It is an arithmetic number, because the mean of its divisors is an integer number (3228511608).

Almost surely, 2^21611261212 is an apocalyptic number.

It is an amenable number.

21611261212 is a deficient number, since it is larger than the sum of its proper divisors (17130878084).

21611261212 is a wasteful number, since it uses less digits than its factorization.

21611261212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131776028 (or 131776026 counting only the distinct ones).

The product of its digits is 576, while the sum is 25.

Adding to 21611261212 its reverse (21216211612), we get a palindrome (42827472824).

The spelling of 21611261212 in words is "twenty-one billion, six hundred eleven million, two hundred sixty-one thousand, two hundred twelve".