1221231230321 has 2 divisors, whose sum is σ = 1221231230322. Its totient is φ = 1221231230320.

The previous prime is 1221231230311. The next prime is 1221231230357. The reversal of 1221231230321 is 1230321321221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 699498049600 + 521733180721 = 836360^2 + 722311^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221231230321 - 2¹⁰ = 1221231229297 is a prime.

It is a super-2 number, since 2×1221231230321² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1221231230311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610615615160 + 610615615161.

It is an arithmetic number, because the mean of its divisors is an integer number (610615615161).

Almost surely, 2^{1221231230321} is an apocalyptic number.

It is an amenable number.

1221231230321 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221231230321 is an equidigital number, since it uses as much as digits as its factorization.

1221231230321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

Adding to 1221231230321 its reverse (1230321321221), we get a palindrome (2451552551542).

The spelling of 1221231230321 in words is "one trillion, two hundred twenty-one billion, two hundred thirty-one million, two hundred thirty thousand, three hundred twenty-one".