21104365 has 4 divisors (see below), whose sum is σ = 25325244. Its totient is φ = 16883488.

The previous prime is 21104341. The next prime is 21104389. The reversal of 21104365 is 56340112.

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

It is an interprime number because it is at equal distance from previous prime (21104341) and next prime (21104389).

It can be written as a sum of positive squares in 2 ways, for example, as 15468489 + 5635876 = 3933^2 + 2374^2 .

It is a cyclic number.

It is not a de Polignac number, because 21104365 - 2⁵ = 21104333 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2110432 + ... + 2110441.

It is an arithmetic number, because the mean of its divisors is an integer number (6331311).

Almost surely, 2^21104365 is an apocalyptic number.

It is an amenable number.

21104365 is a deficient number, since it is larger than the sum of its proper divisors (4220879).

21104365 is an equidigital number, since it uses as much as digits as its factorization.

21104365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4220878.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21104365 is about 4593.9487371977. The cubic root of 21104365 is about 276.3487024708.

Adding to 21104365 its reverse (56340112), we get a palindrome (77444477).

The spelling of 21104365 in words is "twenty-one million, one hundred four thousand, three hundred sixty-five".