1321231217 has 2 divisors, whose sum is σ = 1321231218. Its totient is φ = 1321231216.

The previous prime is 1321231207. The next prime is 1321231237. The reversal of 1321231217 is 7121321231.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1310367601 + 10863616 = 36199^2 + 3296^2 .

It is a cyclic number.

It is not a de Polignac number, because 1321231217 - 2²² = 1317036913 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1321231192 and 1321231201.

It is not a weakly prime, because it can be changed into another prime (1321231207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660615608 + 660615609.

It is an arithmetic number, because the mean of its divisors is an integer number (660615609).

Almost surely, 2^1321231217 is an apocalyptic number.

It is an amenable number.

1321231217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321231217 is an equidigital number, since it uses as much as digits as its factorization.

1321231217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 504, while the sum is 23.

The square root of 1321231217 is about 36348.7443662089. The cubic root of 1321231217 is about 1097.3022644543.

Adding to 1321231217 its reverse (7121321231), we get a palindrome (8442552448).

The spelling of 1321231217 in words is "one billion, three hundred twenty-one million, two hundred thirty-one thousand, two hundred seventeen".