21011968867 has 2 divisors, whose sum is σ = 21011968868. Its totient is φ = 21011968866.

The previous prime is 21011968847. The next prime is 21011968897. The reversal of 21011968867 is 76886911012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21011968867 - 2¹⁹ = 21011444579 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21011968867.

It is not a weakly prime, because it can be changed into another prime (21011968847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505984433 + 10505984434.

It is an arithmetic number, because the mean of its divisors is an integer number (10505984434).

Almost surely, 2^21011968867 is an apocalyptic number.

21011968867 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011968867 is an equidigital number, since it uses as much as digits as its factorization.

21011968867 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 290304, while the sum is 49.

The spelling of 21011968867 in words is "twenty-one billion, eleven million, nine hundred sixty-eight thousand, eight hundred sixty-seven".