1221842563 has 2 divisors, whose sum is σ = 1221842564. Its totient is φ = 1221842562.

The previous prime is 1221842521. The next prime is 1221842569. The reversal of 1221842563 is 3652481221.

It is a strong prime.

It is an emirp because it is prime and its reverse (3652481221) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221842563 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221842569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610921281 + 610921282.

It is an arithmetic number, because the mean of its divisors is an integer number (610921282).

Almost surely, 2^1221842563 is an apocalyptic number.

1221842563 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221842563 is an equidigital number, since it uses as much as digits as its factorization.

1221842563 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23040, while the sum is 34.

The square root of 1221842563 is about 34954.8646542938. The cubic root of 1221842563 is about 1069.0673921711.

The spelling of 1221842563 in words is "one billion, two hundred twenty-one million, eight hundred forty-two thousand, five hundred sixty-three".