1221013217 has 2 divisors, whose sum is σ = 1221013218. Its totient is φ = 1221013216.

The previous prime is 1221013193. The next prime is 1221013229. The reversal of 1221013217 is 7123101221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 988725136 + 232288081 = 31444^2 + 15241^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221013217 - 2⁶ = 1221013153 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221013247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610506608 + 610506609.

It is an arithmetic number, because the mean of its divisors is an integer number (610506609).

Almost surely, 2^1221013217 is an apocalyptic number.

It is an amenable number.

1221013217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221013217 is an equidigital number, since it uses as much as digits as its factorization.

1221013217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 1221013217 is about 34942.9995421114. Note that the first 3 decimals coincide. The cubic root of 1221013217 is about 1068.8254549875.

Adding to 1221013217 its reverse (7123101221), we get a palindrome (8344114438).

The spelling of 1221013217 in words is "one billion, two hundred twenty-one million, thirteen thousand, two hundred seventeen".