21100111101 has 24 divisors (see below), whose sum is σ = 31314440664. Its totient is φ = 13680973440.

The previous prime is 21100111099. The next prime is 21100111103. The reversal of 21100111101 is 10111100112.

It is an interprime number because it is at equal distance from previous prime (21100111099) and next prime (21100111103).

It can be written as a sum of positive squares in 4 ways, for example, as 390023001 + 20710088100 = 19749^2 + 143910^2 .

It is not a de Polignac number, because 21100111101 - 2¹ = 21100111099 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100111103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 901195 + ... + 924311.

It is an arithmetic number, because the mean of its divisors is an integer number (1304768361).

Almost surely, 2^21100111101 is an apocalyptic number.

It is an amenable number.

21100111101 is a deficient number, since it is larger than the sum of its proper divisors (10214329563).

21100111101 is a wasteful number, since it uses less digits than its factorization.

21100111101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25901 (or 25898 counting only the distinct ones).

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

Adding to 21100111101 its reverse (10111100112), we get a palindrome (31211211213).

It can be divided in two parts, 2110011 and 1101, that added together give a palindrome (2111112).

The spelling of 21100111101 in words is "twenty-one billion, one hundred million, one hundred eleven thousand, one hundred one".