21222212012121 has 4 divisors (see below), whose sum is σ = 28296282682832. Its totient is φ = 14148141341412.

The previous prime is 21222212011991. The next prime is 21222212012123. The reversal of 21222212012121 is 12121021222212.

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 21222212012121 - 2¹⁴ = 21222211995737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21222212012123) 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, 3537035335351 + ... + 3537035335356.

It is an arithmetic number, because the mean of its divisors is an integer number (7074070670708).

Almost surely, 2^{21222212012121} is an apocalyptic number.

It is an amenable number.

21222212012121 is a deficient number, since it is larger than the sum of its proper divisors (7074070670711).

21222212012121 is an equidigital number, since it uses as much as digits as its factorization.

21222212012121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7074070670710.

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

Adding to 21222212012121 its reverse (12121021222212), we get a palindrome (33343233234333).

The spelling of 21222212012121 in words is "twenty-one trillion, two hundred twenty-two billion, two hundred twelve million, twelve thousand, one hundred twenty-one".