21111011311 has 16 divisors (see below), whose sum is σ = 23729178816. Its totient is φ = 18635291136.

The previous prime is 21111011287. The next prime is 21111011329. The reversal of 21111011311 is 11311011112.

It is a cyclic number.

It is not a de Polignac number, because 21111011311 - 2¹¹ = 21111009263 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111011291 and 21111011300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111011711) 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, 2037901 + ... + 2048233.

It is an arithmetic number, because the mean of its divisors is an integer number (1483073676).

Almost surely, 2^21111011311 is an apocalyptic number.

21111011311 is a deficient number, since it is larger than the sum of its proper divisors (2618167505).

21111011311 is a wasteful number, since it uses less digits than its factorization.

21111011311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17202.

The product of its (nonzero) digits is 6, while the sum is 13.

Adding to 21111011311 its reverse (11311011112), we get a palindrome (32422022423).

The spelling of 21111011311 in words is "twenty-one billion, one hundred eleven million, eleven thousand, three hundred eleven".