21210111100121 has 4 divisors (see below), whose sum is σ = 21362701827600. Its totient is φ = 21057520372644.

The previous prime is 21210111100081. The next prime is 21210111100133. The reversal of 21210111100121 is 12100111101212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21210111100121 - 2⁴² = 16812064589017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21210111100096 and 21210111100105.

It is not an unprimeable number, because it can be changed into a prime (21210111100021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 76295363531 + ... + 76295363808.

It is an arithmetic number, because the mean of its divisors is an integer number (5340675456900).

Almost surely, 2^{21210111100121} is an apocalyptic number.

It is an amenable number.

21210111100121 is a deficient number, since it is larger than the sum of its proper divisors (152590727479).

21210111100121 is a wasteful number, since it uses less digits than its factorization.

21210111100121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152590727478.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 21210111100121 its reverse (12100111101212), we get a palindrome (33310222201333).

The spelling of 21210111100121 in words is "twenty-one trillion, two hundred ten billion, one hundred eleven million, one hundred thousand, one hundred twenty-one".