12021221221 has 4 divisors (see below), whose sum is σ = 12084159744. Its totient is φ = 11958282700.

The previous prime is 12021221209. The next prime is 12021221231. The reversal of 12021221221 is 12212212021.

It is a happy number.

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 12021221221 - 2¹⁵ = 12021188453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12021221195 and 12021221204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12021221231) 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, 31468975 + ... + 31469356.

It is an arithmetic number, because the mean of its divisors is an integer number (3021039936).

Almost surely, 2^12021221221 is an apocalyptic number.

It is an amenable number.

12021221221 is a deficient number, since it is larger than the sum of its proper divisors (62938523).

12021221221 is an equidigital number, since it uses as much as digits as its factorization.

12021221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62938522.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 12021221221 its reverse (12212212021), we get a palindrome (24233433242).

The spelling of 12021221221 in words is "twelve billion, twenty-one million, two hundred twenty-one thousand, two hundred twenty-one".