21211102121 has 4 divisors (see below), whose sum is σ = 23139384144. Its totient is φ = 19282820100.

The previous prime is 21211102091. The next prime is 21211102127. The reversal of 21211102121 is 12120111212.

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 21211102121 - 2¹⁰ = 21211101097 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211102096 and 21211102105.

It is not an unprimeable number, because it can be changed into a prime (21211102127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 964140995 + ... + 964141016.

It is an arithmetic number, because the mean of its divisors is an integer number (5784846036).

Almost surely, 2^21211102121 is an apocalyptic number.

It is an amenable number.

21211102121 is a deficient number, since it is larger than the sum of its proper divisors (1928282023).

21211102121 is a wasteful number, since it uses less digits than its factorization.

21211102121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1928282022.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21211102121 its reverse (12120111212), we get a palindrome (33331213333).

Subtracting from 21211102121 its reverse (12120111212), we obtain a palindrome (9090990909).

The spelling of 21211102121 in words is "twenty-one billion, two hundred eleven million, one hundred two thousand, one hundred twenty-one".