1321265321 has 2 divisors, whose sum is σ = 1321265322. Its totient is φ = 1321265320.

The previous prime is 1321265299. The next prime is 1321265333. The reversal of 1321265321 is 1235621231.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1160356096 + 160909225 = 34064^2 + 12685^2 .

It is a cyclic number.

It is not a de Polignac number, because 1321265321 - 2¹⁴ = 1321248937 is a prime.

It is not a weakly prime, because it can be changed into another prime (1321265021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660632660 + 660632661.

It is an arithmetic number, because the mean of its divisors is an integer number (660632661).

Almost surely, 2^1321265321 is an apocalyptic number.

It is an amenable number.

1321265321 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321265321 is an equidigital number, since it uses as much as digits as its factorization.

1321265321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 26.

The square root of 1321265321 is about 36349.2134853012. The cubic root of 1321265321 is about 1097.3117056669.

Adding to 1321265321 its reverse (1235621231), we get a palindrome (2556886552).

The spelling of 1321265321 in words is "one billion, three hundred twenty-one million, two hundred sixty-five thousand, three hundred twenty-one".