1213120321 has 4 divisors (see below), whose sum is σ = 1386423232. Its totient is φ = 1039817412.

The previous prime is 1213120319. The next prime is 1213120327. The reversal of 1213120321 is 1230213121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1213120321 - 2¹ = 1213120319 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1213120295 and 1213120304.

It is not an unprimeable number, because it can be changed into a prime (1213120327) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86651445 + ... + 86651458.

It is an arithmetic number, because the mean of its divisors is an integer number (346605808).

Almost surely, 2^1213120321 is an apocalyptic number.

It is an amenable number.

1213120321 is a deficient number, since it is larger than the sum of its proper divisors (173302911).

1213120321 is an equidigital number, since it uses as much as digits as its factorization.

1213120321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173302910.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 1213120321 is about 34829.8768444564. The cubic root of 1213120321 is about 1066.5174342766.

Adding to 1213120321 its reverse (1230213121), we get a palindrome (2443333442).

The spelling of 1213120321 in words is "one billion, two hundred thirteen million, one hundred twenty thousand, three hundred twenty-one".