21311212099 has 2 divisors, whose sum is σ = 21311212100. Its totient is φ = 21311212098.

The previous prime is 21311212067. The next prime is 21311212127. The reversal of 21311212099 is 99021211312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21311212099 - 2⁵ = 21311212067 is a prime.

It is a super-2 number, since 2×21311212099² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21311212099.

It is not a weakly prime, because it can be changed into another prime (21311212199) 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, 10655606049 + 10655606050.

It is an arithmetic number, because the mean of its divisors is an integer number (10655606050).

Almost surely, 2^21311212099 is an apocalyptic number.

21311212099 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311212099 is an equidigital number, since it uses as much as digits as its factorization.

21311212099 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 31.

The spelling of 21311212099 in words is "twenty-one billion, three hundred eleven million, two hundred twelve thousand, ninety-nine".