21201022210121 has 8 divisors (see below), whose sum is σ = 22833363639240. Its totient is φ = 19568894147712.

The previous prime is 21201022210031. The next prime is 21201022210177. The reversal of 21201022210121 is 12101222010212.

It can be written as a sum of positive squares in 4 ways, for example, as 178980609721 + 21022041600400 = 423061^2 + 4584980^2 .

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

It is not a de Polignac number, because 21201022210121 - 2³⁰ = 21199948468297 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21201022210121.

It is not an unprimeable number, because it can be changed into a prime (21201022210021) 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, 53135270 + ... + 53532783.

It is an arithmetic number, because the mean of its divisors is an integer number (2854170454905).

Almost surely, 2^{21201022210121} is an apocalyptic number.

It is an amenable number.

21201022210121 is a deficient number, since it is larger than the sum of its proper divisors (1632341429119).

21201022210121 is a wasteful number, since it uses less digits than its factorization.

21201022210121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106683355.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21201022210121 its reverse (12101222010212), we get a palindrome (33302244220333).

The spelling of 21201022210121 in words is "twenty-one trillion, two hundred one billion, twenty-two million, two hundred ten thousand, one hundred twenty-one".