1215221317 has 2 divisors, whose sum is σ = 1215221318. Its totient is φ = 1215221316.

The previous prime is 1215221299. The next prime is 1215221339. The reversal of 1215221317 is 7131225121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 663629121 + 551592196 = 25761^2 + 23486^2 .

It is an emirp because it is prime and its reverse (7131225121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1215221317 - 2²⁷ = 1081003589 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1215221291 and 1215221300.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1215221347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607610658 + 607610659.

It is an arithmetic number, because the mean of its divisors is an integer number (607610659).

Almost surely, 2^1215221317 is an apocalyptic number.

It is an amenable number.

1215221317 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215221317 is an equidigital number, since it uses as much as digits as its factorization.

1215221317 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 840, while the sum is 25.

The square root of 1215221317 is about 34860.0246270710. The cubic root of 1215221317 is about 1067.1327776156.

Adding to 1215221317 its reverse (7131225121), we get a palindrome (8346446438).

The spelling of 1215221317 in words is "one billion, two hundred fifteen million, two hundred twenty-one thousand, three hundred seventeen".