1215012221 has 2 divisors, whose sum is σ = 1215012222. Its totient is φ = 1215012220.

The previous prime is 1215012143. The next prime is 1215012241. The reversal of 1215012221 is 1222105121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1007364121 + 207648100 = 31739^2 + 14410^2 .

It is a cyclic number.

It is not a de Polignac number, because 1215012221 - 2¹⁸ = 1214750077 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1215012221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1215012241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607506110 + 607506111.

It is an arithmetic number, because the mean of its divisors is an integer number (607506111).

Almost surely, 2^1215012221 is an apocalyptic number.

It is an amenable number.

1215012221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215012221 is an equidigital number, since it uses as much as digits as its factorization.

1215012221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80, while the sum is 17.

The square root of 1215012221 is about 34857.0254181277. The cubic root of 1215012221 is about 1067.0715690135.

Adding to 1215012221 its reverse (1222105121), we get a palindrome (2437117342).

The spelling of 1215012221 in words is "one billion, two hundred fifteen million, twelve thousand, two hundred twenty-one".