21202112222121 has 4 divisors (see below), whose sum is σ = 28269482962832. Its totient is φ = 14134741481412.

The previous prime is 21202112222119. The next prime is 21202112222131. The reversal of 21202112222121 is 12122221120212.

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 not a de Polignac number, because 21202112222121 - 2¹ = 21202112222119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21202112222131) 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, 3533685370351 + ... + 3533685370356.

It is an arithmetic number, because the mean of its divisors is an integer number (7067370740708).

Almost surely, 2^{21202112222121} is an apocalyptic number.

It is an amenable number.

21202112222121 is a deficient number, since it is larger than the sum of its proper divisors (7067370740711).

21202112222121 is an equidigital number, since it uses as much as digits as its factorization.

21202112222121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7067370740710.

The product of its (nonzero) digits is 256, while the sum is 21.

Adding to 21202112222121 its reverse (12122221120212), we get a palindrome (33324333342333).

The spelling of 21202112222121 in words is "twenty-one trillion, two hundred two billion, one hundred twelve million, two hundred twenty-two thousand, one hundred twenty-one".