1220312321 has 2 divisors, whose sum is σ = 1220312322. Its totient is φ = 1220312320.

The previous prime is 1220312299. The next prime is 1220312323. The reversal of 1220312321 is 1232130221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 926532721 + 293779600 = 30439^2 + 17140^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220312321 - 2¹⁸ = 1220050177 is a prime.

It is a Sophie Germain prime.

Together with 1220312323, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1220312321.

It is not a weakly prime, because it can be changed into another prime (1220312323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610156160 + 610156161.

It is an arithmetic number, because the mean of its divisors is an integer number (610156161).

Almost surely, 2^1220312321 is an apocalyptic number.

It is an amenable number.

1220312321 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220312321 is an equidigital number, since it uses as much as digits as its factorization.

1220312321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 1220312321 is about 34932.9689691558. The cubic root of 1220312321 is about 1068.6209038647.

Adding to 1220312321 its reverse (1232130221), we get a palindrome (2452442542).

The spelling of 1220312321 in words is "one billion, two hundred twenty million, three hundred twelve thousand, three hundred twenty-one".