1212215321 has 2 divisors, whose sum is σ = 1212215322. Its totient is φ = 1212215320.

The previous prime is 1212215309. The next prime is 1212215327. The reversal of 1212215321 is 1235122121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1211805721 + 409600 = 34811^2 + 640^2 .

It is an emirp because it is prime and its reverse (1235122121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1212215321 - 2¹⁸ = 1211953177 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1212215293 and 1212215302.

It is not a weakly prime, because it can be changed into another prime (1212215327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606107660 + 606107661.

It is an arithmetic number, because the mean of its divisors is an integer number (606107661).

Almost surely, 2^1212215321 is an apocalyptic number.

It is an amenable number.

1212215321 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212215321 is an equidigital number, since it uses as much as digits as its factorization.

1212215321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 240, while the sum is 20.

The square root of 1212215321 is about 34816.8827007818. The cubic root of 1212215321 is about 1066.2521573769.

Adding to 1212215321 its reverse (1235122121), we get a palindrome (2447337442).

The spelling of 1212215321 in words is "one billion, two hundred twelve million, two hundred fifteen thousand, three hundred twenty-one".