21121212120121 has 8 divisors (see below), whose sum is σ = 21250935362240. Its totient is φ = 20991490649712.

The previous prime is 21121212120049. The next prime is 21121212120133. The reversal of 21121212120121 is 12102121212112.

It is a happy number.

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 21121212120121 - 2³¹ = 21119064636473 is a prime.

It is a super-2 number, since 2×21121212120121² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121212124121) 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, 29788795 + ... + 30489583.

It is an arithmetic number, because the mean of its divisors is an integer number (2656366920280).

Almost surely, 2^{21121212120121} is an apocalyptic number.

It is an amenable number.

21121212120121 is a deficient number, since it is larger than the sum of its proper divisors (129723242119).

21121212120121 is a wasteful number, since it uses less digits than its factorization.

21121212120121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 885855.

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

Adding to 21121212120121 its reverse (12102121212112), we get a palindrome (33223333332233).

The spelling of 21121212120121 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twelve million, one hundred twenty thousand, one hundred twenty-one".