21212000121121 has 8 divisors (see below), whose sum is σ = 21218656876200. Its totient is φ = 21205344421632.

The previous prime is 21212000121097. The next prime is 21212000121173. The reversal of 21212000121121 is 12112100021212.

It can be written as a sum of positive squares in 4 ways, for example, as 1064146980625 + 20147853140496 = 1031575^2 + 4488636^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21212000121121 - 2¹⁵ = 21212000088353 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21212000121095 and 21212000121104.

It is not an unprimeable number, because it can be changed into a prime (21212001121121) 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, 40934955 + ... + 41449903.

It is an arithmetic number, because the mean of its divisors is an integer number (2652332109525).

Almost surely, 2^{21212000121121} is an apocalyptic number.

It is an amenable number.

21212000121121 is a deficient number, since it is larger than the sum of its proper divisors (6656755079).

21212000121121 is an equidigital number, since it uses as much as digits as its factorization.

21212000121121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 527795.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21212000121121 its reverse (12112100021212), we get a palindrome (33324100142333).

Subtracting from 21212000121121 its reverse (12112100021212), we obtain a palindrome (9099900099909).

The spelling of 21212000121121 in words is "twenty-one trillion, two hundred twelve billion, one hundred twenty-one thousand, one hundred twenty-one".