1212023221 has 4 divisors (see below), whose sum is σ = 1212214732. Its totient is φ = 1211831712.

The previous prime is 1212023191. The next prime is 1212023251. The reversal of 1212023221 is 1223202121.

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: 1223202121 = 19 ⋅64379059.

It is an interprime number because it is at equal distance from previous prime (1212023191) and next prime (1212023251).

It can be written as a sum of positive squares in 2 ways, for example, as 811623121 + 400400100 = 28489^2 + 20010^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212023221 - 2¹⁵ = 1211990453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1212023195 and 1212023204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212023251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85926 + ... + 99031.

It is an arithmetic number, because the mean of its divisors is an integer number (303053683).

Almost surely, 2^1212023221 is an apocalyptic number.

It is an amenable number.

1212023221 is a deficient number, since it is larger than the sum of its proper divisors (191511).

1212023221 is an equidigital number, since it uses as much as digits as its factorization.

1212023221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191510.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 1212023221 is about 34814.1238723596. The cubic root of 1212023221 is about 1066.1958313385.

Adding to 1212023221 its reverse (1223202121), we get a palindrome (2435225342).

The spelling of 1212023221 in words is "one billion, two hundred twelve million, twenty-three thousand, two hundred twenty-one".