21011101011 has 24 divisors (see below), whose sum is σ = 30787376256. Its totient is φ = 13806616320.

The previous prime is 21011101009. The next prime is 21011101103. The reversal of 21011101011 is 11010111012.

It is not a de Polignac number, because 21011101011 - 2¹ = 21011101009 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 = 21011100984 and 21011101002.

It is not an unprimeable number, because it can be changed into a prime (21011108011) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 127006 + ... + 241148.

It is an arithmetic number, because the mean of its divisors is an integer number (1282807344).

Almost surely, 2^21011101011 is an apocalyptic number.

21011101011 is a deficient number, since it is larger than the sum of its proper divisors (9776275245).

21011101011 is a wasteful number, since it uses less digits than its factorization.

21011101011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114443 (or 114440 counting only the distinct ones).

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

Adding to 21011101011 its reverse (11010111012), we get a palindrome (32021212023).

The spelling of 21011101011 in words is "twenty-one billion, eleven million, one hundred one thousand, eleven".