21110001111 has 16 divisors (see below), whose sum is σ = 31804147200. Its totient is φ = 13834801944.

The previous prime is 21110001103. The next prime is 21110001131. The reversal of 21110001111 is 11110001112.

It is not a de Polignac number, because 21110001111 - 2³ = 21110001103 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21110001093 and 21110001102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110001131) 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 15 ways as a sum of consecutive naturals, for example, 6624271 + ... + 6627456.

It is an arithmetic number, because the mean of its divisors is an integer number (1987759200).

Almost surely, 2^21110001111 is an apocalyptic number.

21110001111 is a deficient number, since it is larger than the sum of its proper divisors (10694146089).

21110001111 is a wasteful number, since it uses less digits than its factorization.

21110001111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13251795 (or 13251789 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 9.

Adding to 21110001111 its reverse (11110001112), we get a palindrome (32220002223).

Subtracting from 21110001111 its reverse (11110001112), we obtain a palindrome (9999999999).

The spelling of 21110001111 in words is "twenty-one billion, one hundred ten million, one thousand, one hundred eleven".