21001101111 has 24 divisors (see below), whose sum is σ = 30646646784. Its totient is φ = 13857104400.

The previous prime is 21001101101. The next prime is 21001101137. The reversal of 21001101111 is 11110110012.

It is not a de Polignac number, because 21001101111 - 2⁹ = 21001100599 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 = 21001101093 and 21001101102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001101101) 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, 1098940 + ... + 1117886.

It is an arithmetic number, because the mean of its divisors is an integer number (1276943616).

Almost surely, 2^21001101111 is an apocalyptic number.

21001101111 is a deficient number, since it is larger than the sum of its proper divisors (9645545673).

21001101111 is a wasteful number, since it uses less digits than its factorization.

21001101111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20211 (or 20208 counting only the distinct ones).

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

Adding to 21001101111 its reverse (11110110012), we get a palindrome (32111211123).

The spelling of 21001101111 in words is "twenty-one billion, one million, one hundred one thousand, one hundred eleven".