12020021221 has 4 divisors (see below), whose sum is σ = 12944638252. Its totient is φ = 11095404192.

The previous prime is 12020021203. The next prime is 12020021231. The reversal of 12020021221 is 12212002021.

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: 12212002021 = 43 ⋅284000047.

It can be written as a sum of positive squares in 2 ways, for example, as 4535349025 + 7484672196 = 67345^2 + 86514^2 .

It is a cyclic number.

It is not a de Polignac number, because 12020021221 - 2⁹ = 12020020709 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 924617017 = 12020021221 / (1 + 2 + 0 + 2 + 0 + 0 + 2 + 1 + 2 + 2 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12020021201) 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, 462308496 + ... + 462308521.

It is an arithmetic number, because the mean of its divisors is an integer number (3236159563).

Almost surely, 2^12020021221 is an apocalyptic number.

It is an amenable number.

12020021221 is a deficient number, since it is larger than the sum of its proper divisors (924617031).

12020021221 is an equidigital number, since it uses as much as digits as its factorization.

12020021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 924617030.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 12020021221 its reverse (12212002021), we get a palindrome (24232023242).

The spelling of 12020021221 in words is "twelve billion, twenty million, twenty-one thousand, two hundred twenty-one".