21043111999 has 32 divisors (see below), whose sum is σ = 27084395520. Its totient is φ = 15890764032.

The previous prime is 21043111987. The next prime is 21043112011. The reversal of 21043111999 is 99911134012.

It is an interprime number because it is at equal distance from previous prime (21043111987) and next prime (21043112011).

It is not a de Polignac number, because 21043111999 - 2¹⁵ = 21043079231 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21043111499) 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 in 31 ways as a sum of consecutive naturals, for example, 966667 + ... + 988195.

It is an arithmetic number, because the mean of its divisors is an integer number (846387360).

Almost surely, 2^21043111999 is an apocalyptic number.

21043111999 is a deficient number, since it is larger than the sum of its proper divisors (6041283521).

21043111999 is a wasteful number, since it uses less digits than its factorization.

21043111999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22039.

The product of its (nonzero) digits is 17496, while the sum is 40.

The spelling of 21043111999 in words is "twenty-one billion, forty-three million, one hundred eleven thousand, nine hundred ninety-nine".