21211212120121 has 8 divisors (see below), whose sum is σ = 21287138955264. Its totient is φ = 21135288420960.

The previous prime is 21211212120083. The next prime is 21211212120167. The reversal of 21211212120121 is 12102121211212.

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 21211212120121 - 2¹¹ = 21211212118073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21211212120181) 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, 13214296 + ... + 14732278.

It is an arithmetic number, because the mean of its divisors is an integer number (2660892369408).

Almost surely, 2^{21211212120121} is an apocalyptic number.

It is an amenable number.

21211212120121 is a deficient number, since it is larger than the sum of its proper divisors (75926835143).

21211212120121 is a wasteful number, since it uses less digits than its factorization.

21211212120121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1567991.

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

Adding to 21211212120121 its reverse (12102121211212), we get a palindrome (33313333331333).

The spelling of 21211212120121 in words is "twenty-one trillion, two hundred eleven billion, two hundred twelve million, one hundred twenty thousand, one hundred twenty-one".