21021221111121 has 48 divisors (see below), whose sum is σ = 37867039441920. Its totient is φ = 10917045272160.

The previous prime is 21021221111113. The next prime is 21021221111131. The reversal of 21021221111121 is 12111112212012.

It is a happy number.

21021221111121 is a `hidden beast` number, since 210 + 2 + 1 + 221 + 111 + 121 = 666.

It is not a de Polignac number, because 21021221111121 - 2³ = 21021221111113 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21021221111094 and 21021221111103.

It is not an unprimeable number, because it can be changed into a prime (21021221111131) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1795155 + ... + 6727928.

It is an arithmetic number, because the mean of its divisors is an integer number (788896655040).

Almost surely, 2^{21021221111121} is an apocalyptic number.

21021221111121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21021221111121 is a deficient number, since it is larger than the sum of its proper divisors (16845818330799).

21021221111121 is a wasteful number, since it uses less digits than its factorization.

21021221111121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8526666 (or 8526663 counting only the distinct ones).

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

Adding to 21021221111121 its reverse (12111112212012), we get a palindrome (33132333323133).

The spelling of 21021221111121 in words is "twenty-one trillion, twenty-one billion, two hundred twenty-one million, one hundred eleven thousand, one hundred twenty-one".