1312221221 has 4 divisors (see below), whose sum is σ = 1319471244. Its totient is φ = 1304971200.

The previous prime is 1312221199. The next prime is 1312221233. The reversal of 1312221221 is 1221222131.

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 559322500 + 752898721 = 23650^2 + 27439^2 .

It is a cyclic number.

It is not a de Polignac number, because 1312221221 - 2¹⁰ = 1312220197 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1312221221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1312221241) 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, 3624740 + ... + 3625101.

It is an arithmetic number, because the mean of its divisors is an integer number (329867811).

Almost surely, 2^1312221221 is an apocalyptic number.

It is an amenable number.

1312221221 is a deficient number, since it is larger than the sum of its proper divisors (7250023).

1312221221 is an equidigital number, since it uses as much as digits as its factorization.

1312221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7250022.

The product of its digits is 96, while the sum is 17.

The square root of 1312221221 is about 36224.5941454145. The cubic root of 1312221221 is about 1094.8022608819.

Adding to 1312221221 its reverse (1221222131), we get a palindrome (2533443352).

It can be divided in two parts, 13122 and 21221, that added together give a palindrome (34343).

The spelling of 1312221221 in words is "one billion, three hundred twelve million, two hundred twenty-one thousand, two hundred twenty-one".