21210221111121 has 144 divisors (see below), whose sum is σ = 36306934210560. Its totient is φ = 11895435921600.

The previous prime is 21210221111117. The next prime is 21210221111129. The reversal of 21210221111121 is 12111112201212.

It is a happy number.

21210221111121 is a `hidden beast` number, since 2 + 1 + 210 + 221 + 111 + 121 = 666.

It is not a de Polignac number, because 21210221111121 - 2² = 21210221111117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21210221111094 and 21210221111103.

It is not an unprimeable number, because it can be changed into a prime (21210221111129) 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 143 ways as a sum of consecutive naturals, for example, 3175654860 + ... + 3175661538.

Almost surely, 2^{21210221111121} is an apocalyptic number.

21210221111121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21210221111121 is a deficient number, since it is larger than the sum of its proper divisors (15096713099439).

21210221111121 is a wasteful number, since it uses less digits than its factorization.

21210221111121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7416 (or 7406 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 21210221111121 its reverse (12111112201212), we get a palindrome (33321333312333).

The spelling of 21210221111121 in words is "twenty-one trillion, two hundred ten billion, two hundred twenty-one million, one hundred eleven thousand, one hundred twenty-one".