21011099999 has 2 divisors, whose sum is σ = 21011100000. Its totient is φ = 21011099998.

The previous prime is 21011099953. The next prime is 21011100017. The reversal of 21011099999 is 99999011012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21011099999 - 2⁸ = 21011099743 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21011099929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505549999 + 10505550000.

It is an arithmetic number, because the mean of its divisors is an integer number (10505550000).

Almost surely, 2^21011099999 is an apocalyptic number.

21011099999 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011099999 is an equidigital number, since it uses as much as digits as its factorization.

21011099999 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 50.

The spelling of 21011099999 in words is "twenty-one billion, eleven million, ninety-nine thousand, nine hundred ninety-nine".