21121121211 has 8 divisors (see below), whose sum is σ = 28163033664. Its totient is φ = 14079978120.

The previous prime is 21121121101. The next prime is 21121121233. The reversal of 21121121211 is 11212112112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21121121211 - 2⁷ = 21121121083 is a prime.

It is a super-2 number, since 2×21121121211² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121121261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 124905 + ... + 240506.

It is an arithmetic number, because the mean of its divisors is an integer number (3520379208).

Almost surely, 2^21121121211 is an apocalyptic number.

21121121211 is a deficient number, since it is larger than the sum of its proper divisors (7041912453).

21121121211 is a wasteful number, since it uses less digits than its factorization.

21121121211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 384681.

The product of its digits is 16, while the sum is 15.

Adding to 21121121211 its reverse (11212112112), we get a palindrome (32333233323).

Subtracting from 21121121211 its reverse (11212112112), we obtain a palindrome (9909009099).

It can be divided in two parts, 2112 and 1121211, that multiplied together give a palindrome (2367997632).

The spelling of 21121121211 in words is "twenty-one billion, one hundred twenty-one million, one hundred twenty-one thousand, two hundred eleven".