1221025217 has 2 divisors, whose sum is σ = 1221025218. Its totient is φ = 1221025216.

The previous prime is 1221025171. The next prime is 1221025231. The reversal of 1221025217 is 7125201221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 853574656 + 367450561 = 29216^2 + 19169^2 .

It is an emirp because it is prime and its reverse (7125201221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221025217 - 2¹⁶ = 1220959681 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221025192 and 1221025201.

It is not a weakly prime, because it can be changed into another prime (1221025297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610512608 + 610512609.

It is an arithmetic number, because the mean of its divisors is an integer number (610512609).

Almost surely, 2^1221025217 is an apocalyptic number.

It is an amenable number.

1221025217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221025217 is an equidigital number, since it uses as much as digits as its factorization.

1221025217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 1221025217 is about 34943.1712499023. The cubic root of 1221025217 is about 1068.8289564138.

Adding to 1221025217 its reverse (7125201221), we get a palindrome (8346226438).

The spelling of 1221025217 in words is "one billion, two hundred twenty-one million, twenty-five thousand, two hundred seventeen".