21211101200121 has 24 divisors (see below), whose sum is σ = 33238014274080. Its totient is φ = 11995674308352.

The previous prime is 21211101200099. The next prime is 21211101200123. The reversal of 21211101200121 is 12100210111212.

It is a happy number.

It is not a de Polignac number, because 21211101200121 - 2¹⁹ = 21211100675833 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21211101200121.

It is not an unprimeable number, because it can be changed into a prime (21211101200123) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 743765151 + ... + 743793668.

It is an arithmetic number, because the mean of its divisors is an integer number (1384917261420).

Almost surely, 2^{21211101200121} is an apocalyptic number.

21211101200121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21211101200121 is a deficient number, since it is larger than the sum of its proper divisors (12026913073959).

21211101200121 is a wasteful number, since it uses less digits than its factorization.

21211101200121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1487558933 (or 1487558926 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21211101200121 its reverse (12100210111212), we get a palindrome (33311311311333).

The spelling of 21211101200121 in words is "twenty-one trillion, two hundred eleven billion, one hundred one million, two hundred thousand, one hundred twenty-one".