1221221249 has 2 divisors, whose sum is σ = 1221221250. Its totient is φ = 1221221248.

The previous prime is 1221221207. The next prime is 1221221279. The reversal of 1221221249 is 9421221221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 994267024 + 226954225 = 31532^2 + 15065^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221221249 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221221279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610610624 + 610610625.

It is an arithmetic number, because the mean of its divisors is an integer number (610610625).

Almost surely, 2^1221221249 is an apocalyptic number.

It is an amenable number.

1221221249 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221221249 is an equidigital number, since it uses as much as digits as its factorization.

1221221249 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1152, while the sum is 26.

The square root of 1221221249 is about 34945.9761489073. The cubic root of 1221221249 is about 1068.8861524660.

The spelling of 1221221249 in words is "one billion, two hundred twenty-one million, two hundred twenty-one thousand, two hundred forty-nine".