1221319999 has 2 divisors, whose sum is σ = 1221320000. Its totient is φ = 1221319998.

The previous prime is 1221319993. The next prime is 1221320021. The reversal of 1221319999 is 9999131221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221319999 - 2³ = 1221319991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221319991) 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 as a sum of consecutive naturals, namely, 610659999 + 610660000.

It is an arithmetic number, because the mean of its divisors is an integer number (610660000).

Almost surely, 2^1221319999 is an apocalyptic number.

1221319999 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221319999 is an equidigital number, since it uses as much as digits as its factorization.

1221319999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 78732, while the sum is 46.

The square root of 1221319999 is about 34947.3890154901. The cubic root of 1221319999 is about 1068.9149623323.

The spelling of 1221319999 in words is "one billion, two hundred twenty-one million, three hundred nineteen thousand, nine hundred ninety-nine".