1021099999 has 2 divisors, whose sum is σ = 1021100000. Its totient is φ = 1021099998.

The previous prime is 1021099997. The next prime is 1021100009. The reversal of 1021099999 is 9999901201.

It is a weak prime.

It is an emirp because it is prime and its reverse (9999901201) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1021099999 - 2¹ = 1021099997 is a prime.

Together with 1021099997, it forms a pair of twin primes.

1021099999 is a modest number, since divided by 99999 gives 10210 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021099991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510549999 + 510550000.

It is an arithmetic number, because the mean of its divisors is an integer number (510550000).

Almost surely, 2^1021099999 is an apocalyptic number.

1021099999 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021099999 is an equidigital number, since it uses as much as digits as its factorization.

1021099999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 118098, while the sum is 49.

The square root of 1021099999 is about 31954.6553572402. The cubic root of 1021099999 is about 1006.9844370664.

The spelling of 1021099999 in words is "one billion, twenty-one million, ninety-nine thousand, nine hundred ninety-nine".