21212101122121 has 16 divisors (see below), whose sum is σ = 26109301929984. Its totient is φ = 16781850535104.

The previous prime is 21212101122109. The next prime is 21212101122133. The reversal of 21212101122121 is 12122110121212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21212101122109) and next prime (21212101122133).

It is a cyclic number.

It is not a de Polignac number, because 21212101122121 - 2²⁹ = 21211564251209 is a prime.

It is a super-3 number, since 3×21212101122121³ (a number of 41 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21212101122181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8239465 + ... + 10502998.

It is an arithmetic number, because the mean of its divisors is an integer number (1631831370624).

Almost surely, 2^{21212101122121} is an apocalyptic number.

It is an amenable number.

21212101122121 is a deficient number, since it is larger than the sum of its proper divisors (4897200807863).

21212101122121 is a wasteful number, since it uses less digits than its factorization.

21212101122121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18754920.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21212101122121 its reverse (12122110121212), we get a palindrome (33334211243333).

The spelling of 21212101122121 in words is "twenty-one trillion, two hundred twelve billion, one hundred one million, one hundred twenty-two thousand, one hundred twenty-one".