1321212121321 has 4 divisors (see below), whose sum is σ = 1321486407252. Its totient is φ = 1320937835392.

The previous prime is 1321212121297. The next prime is 1321212121373. The reversal of 1321212121321 is 1231212121231.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 154477297296 + 1166734824025 = 393036^2 + 1080155^2 .

It is a cyclic number.

It is not a de Polignac number, because 1321212121321 - 2¹⁹ = 1321211597033 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1321212121292 and 1321212121301.

It is not an unprimeable number, because it can be changed into a prime (1321212221321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 137135740 + ... + 137145373.

It is an arithmetic number, because the mean of its divisors is an integer number (330371601813).

Almost surely, 2^{1321212121321} is an apocalyptic number.

It is an amenable number.

1321212121321 is a deficient number, since it is larger than the sum of its proper divisors (274285931).

1321212121321 is an equidigital number, since it uses as much as digits as its factorization.

1321212121321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274285930.

The product of its digits is 288, while the sum is 22.

Adding to 1321212121321 its reverse (1231212121231), we get a palindrome (2552424242552).

The spelling of 1321212121321 in words is "one trillion, three hundred twenty-one billion, two hundred twelve million, one hundred twenty-one thousand, three hundred twenty-one".