21111202222121 has 4 divisors (see below), whose sum is σ = 23030402424144. Its totient is φ = 19192002020100.

The previous prime is 21111202222067. The next prime is 21111202222169. The reversal of 21111202222121 is 12122220211112.

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 a de Polignac number, because none of the positive numbers 2^k-21111202222121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111202222093 and 21111202222102.

It is not an unprimeable number, because it can be changed into a prime (21111202222171) 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, 959600100995 + ... + 959600101016.

It is an arithmetic number, because the mean of its divisors is an integer number (5757600606036).

Almost surely, 2^{21111202222121} is an apocalyptic number.

It is an amenable number.

21111202222121 is a deficient number, since it is larger than the sum of its proper divisors (1919200202023).

21111202222121 is a wasteful number, since it uses less digits than its factorization.

21111202222121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1919200202022.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21111202222121 its reverse (12122220211112), we get a palindrome (33233422433233).

The spelling of 21111202222121 in words is "twenty-one trillion, one hundred eleven billion, two hundred two million, two hundred twenty-two thousand, one hundred twenty-one".