21011111011 has 16 divisors (see below), whose sum is σ = 23505292800. Its totient is φ = 18620324800.

The previous prime is 21011111003. The next prime is 21011111029. The reversal of 21011111011 is 11011111012.

It is not a de Polignac number, because 21011111011 - 2³ = 21011111003 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21011111711) 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, 81631 + ... + 220648.

It is an arithmetic number, because the mean of its divisors is an integer number (1469080800).

Almost surely, 2^21011111011 is an apocalyptic number.

21011111011 is a deficient number, since it is larger than the sum of its proper divisors (2494181789).

21011111011 is a wasteful number, since it uses less digits than its factorization.

21011111011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302450.

The product of its (nonzero) digits is 2, while the sum is 10.

Adding to 21011111011 its reverse (11011111012), we get a palindrome (32022222023).

Subtracting from 21011111011 its reverse (11011111012), we obtain a palindrome (9999999999).

It can be divided in two parts, 210111 and 11011, that added together give a palindrome (221122).

The spelling of 21011111011 in words is "twenty-one billion, eleven million, one hundred eleven thousand, eleven".