21021212111121 has 8 divisors (see below), whose sum is σ = 31142536460960. Its totient is φ = 14014141407396.

The previous prime is 21021212111051. The next prime is 21021212111161. The reversal of 21021212111121 is 12111121212012.

It is a happy number.

21021212111121 is a `hidden beast` number, since 210 + 2 + 121 + 211 + 1 + 121 = 666.

It is not a de Polignac number, because 21021212111121 - 2¹³ = 21021212102929 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21021212111094 and 21021212111103.

It is not an unprimeable number, because it can be changed into a prime (21021212111161) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 389281705735 + ... + 389281705788.

It is an arithmetic number, because the mean of its divisors is an integer number (3892817057620).

Almost surely, 2^{21021212111121} is an apocalyptic number.

It is an amenable number.

21021212111121 is a deficient number, since it is larger than the sum of its proper divisors (10121324349839).

21021212111121 is an equidigital number, since it uses as much as digits as its factorization.

21021212111121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778563411532 (or 778563411526 counting only the distinct ones).

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

Adding to 21021212111121 its reverse (12111121212012), we get a palindrome (33132333323133).

The spelling of 21021212111121 in words is "twenty-one trillion, twenty-one billion, two hundred twelve million, one hundred eleven thousand, one hundred twenty-one".