1221312311321 has 8 divisors (see below), whose sum is σ = 1226558884704. Its totient is φ = 1216075116960.

The previous prime is 1221312311293. The next prime is 1221312311389. The reversal of 1221312311321 is 1231132131221.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221312311321 - 2⁶ = 1221312311257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221312313321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2083700 + ... + 2604693.

It is an arithmetic number, because the mean of its divisors is an integer number (153319860588).

Almost surely, 2^{1221312311321} is an apocalyptic number.

It is an amenable number.

1221312311321 is a deficient number, since it is larger than the sum of its proper divisors (5246573383).

1221312311321 is an equidigital number, since it uses as much as digits as its factorization.

1221312311321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4689511.

The product of its digits is 432, while the sum is 23.

Adding to 1221312311321 its reverse (1231132131221), we get a palindrome (2452444442542).

The spelling of 1221312311321 in words is "one trillion, two hundred twenty-one billion, three hundred twelve million, three hundred eleven thousand, three hundred twenty-one".