21111002111 has 16 divisors (see below), whose sum is σ = 22197846528. Its totient is φ = 20038524000.

The previous prime is 21111002063. The next prime is 21111002117. The reversal of 21111002111 is 11120011112.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111002111 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111002092 and 21111002101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111002117) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4099040 + ... + 4104186.

It is an arithmetic number, because the mean of its divisors is an integer number (1387365408).

Almost surely, 2^21111002111 is an apocalyptic number.

21111002111 is a deficient number, since it is larger than the sum of its proper divisors (1086844417).

21111002111 is a wasteful number, since it uses less digits than its factorization.

21111002111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6502.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21111002111 its reverse (11120011112), we get a palindrome (32231013223).

Subtracting from 21111002111 its reverse (11120011112), we obtain a palindrome (9990990999).

The spelling of 21111002111 in words is "twenty-one billion, one hundred eleven million, two thousand, one hundred eleven".