12021122221 has 4 divisors (see below), whose sum is σ = 12156191100. Its totient is φ = 11886053344.

The previous prime is 12021122209. The next prime is 12021122233. The reversal of 12021122221 is 12222112021.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12222112021 = 7 ⋅1746016003.

It is an interprime number because it is at equal distance from previous prime (12021122209) and next prime (12021122233).

It can be written as a sum of positive squares in 2 ways, for example, as 6713999721 + 5307122500 = 81939^2 + 72850^2 .

It is a cyclic number.

It is not a de Polignac number, because 12021122221 - 2¹³ = 12021114029 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12021122195 and 12021122204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12021129221) 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, 67534306 + ... + 67534483.

It is an arithmetic number, because the mean of its divisors is an integer number (3039047775).

Almost surely, 2^12021122221 is an apocalyptic number.

It is an amenable number.

12021122221 is a deficient number, since it is larger than the sum of its proper divisors (135068879).

12021122221 is an equidigital number, since it uses as much as digits as its factorization.

12021122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135068878.

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

Adding to 12021122221 its reverse (12222112021), we get a palindrome (24243234242).

The spelling of 12021122221 in words is "twelve billion, twenty-one million, one hundred twenty-two thousand, two hundred twenty-one".