1221665299 has 2 divisors, whose sum is σ = 1221665300. Its totient is φ = 1221665298.

The previous prime is 1221665279. The next prime is 1221665369. The reversal of 1221665299 is 9925661221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221665299 - 2¹⁷ = 1221534227 is a prime.

It is a super-2 number, since 2×1221665299² = 2984932205561518802, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1221665279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610832649 + 610832650.

It is an arithmetic number, because the mean of its divisors is an integer number (610832650).

Almost surely, 2^1221665299 is an apocalyptic number.

1221665299 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221665299 is an equidigital number, since it uses as much as digits as its factorization.

1221665299 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 116640, while the sum is 43.

The square root of 1221665299 is about 34952.3289495850. The cubic root of 1221665299 is about 1069.0156898396.

The spelling of 1221665299 in words is "one billion, two hundred twenty-one million, six hundred sixty-five thousand, two hundred ninety-nine".