21100002109 has 4 divisors (see below), whose sum is σ = 21293580220. Its totient is φ = 20906424000.

The previous prime is 21100002107. The next prime is 21100002127. The reversal of 21100002109 is 90120000112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15824885209 + 5275116900 = 125797^2 + 72630^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100002109 - 2¹ = 21100002107 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100002092 and 21100002101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100002103) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96788892 + ... + 96789109.

It is an arithmetic number, because the mean of its divisors is an integer number (5323395055).

Almost surely, 2^21100002109 is an apocalyptic number.

It is an amenable number.

21100002109 is a deficient number, since it is larger than the sum of its proper divisors (193578111).

21100002109 is a wasteful number, since it uses less digits than its factorization.

21100002109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193578110.

The product of its (nonzero) digits is 36, while the sum is 16.

The spelling of 21100002109 in words is "twenty-one billion, one hundred million, two thousand, one hundred nine".