1221289356899 has 4 divisors (see below), whose sum is σ = 1226155051800. Its totient is φ = 1216423662000.

The previous prime is 1221289356863. The next prime is 1221289356901. The reversal of 1221289356899 is 9986539821221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221289356899 - 2⁴⁰ = 121777729123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221289356829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2432847074 + ... + 2432847575.

It is an arithmetic number, because the mean of its divisors is an integer number (306538762950).

Almost surely, 2^{1221289356899} is an apocalyptic number.

1221289356899 is a deficient number, since it is larger than the sum of its proper divisors (4865694901).

1221289356899 is an equidigital number, since it uses as much as digits as its factorization.

1221289356899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4865694900.

The product of its digits is 33592320, while the sum is 65.

The spelling of 1221289356899 in words is "one trillion, two hundred twenty-one billion, two hundred eighty-nine million, three hundred fifty-six thousand, eight hundred ninety-nine".