21010111011 has 12 divisors (see below), whose sum is σ = 32133111192. Its totient is φ = 13182814656.

The previous prime is 21010110983. The next prime is 21010111013. The reversal of 21010111011 is 11011101012.

It is not a de Polignac number, because 21010111011 - 2¹⁴ = 21010094627 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 = 21010110984 and 21010111002.

It is not an unprimeable number, because it can be changed into a prime (21010111013) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 68660341 + ... + 68660646.

It is an arithmetic number, because the mean of its divisors is an integer number (2677759266).

Almost surely, 2^21010111011 is an apocalyptic number.

21010111011 is a deficient number, since it is larger than the sum of its proper divisors (11123000181).

21010111011 is a wasteful number, since it uses less digits than its factorization.

21010111011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137321010 (or 137321007 counting only the distinct ones).

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

Adding to 21010111011 its reverse (11011101012), we get a palindrome (32021212023).

Subtracting from 21010111011 its reverse (11011101012), we obtain a palindrome (9999009999).

The spelling of 21010111011 in words is "twenty-one billion, ten million, one hundred eleven thousand, eleven".