21104113 has 4 divisors (see below), whose sum is σ = 21114100. Its totient is φ = 21094128.

The previous prime is 21104071. The next prime is 21104131. The reversal of 21104113 is 31140112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 18173169 + 2930944 = 4263^2 + 1712^2 .

It is a cyclic number.

It is not a de Polignac number, because 21104113 - 2¹⁷ = 20973041 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21104093 and 21104102.

It is not an unprimeable number, because it can be changed into a prime (21104143) 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, 438 + ... + 6511.

It is an arithmetic number, because the mean of its divisors is an integer number (5278525).

Almost surely, 2^21104113 is an apocalyptic number.

It is an amenable number.

21104113 is a deficient number, since it is larger than the sum of its proper divisors (9987).

21104113 is an equidigital number, since it uses as much as digits as its factorization.

21104113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9986.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 21104113 is about 4593.9213097309. The cubic root of 21104113 is about 276.3476025380.

Adding to 21104113 its reverse (31140112), we get a palindrome (52244225).

The spelling of 21104113 in words is "twenty-one million, one hundred four thousand, one hundred thirteen".