21104635 has 4 divisors (see below), whose sum is σ = 25325568. Its totient is φ = 16883704.

The previous prime is 21104591. The next prime is 21104641. The reversal of 21104635 is 53640112.

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

It is a cyclic number.

It is not a de Polignac number, because 21104635 - 2⁷ = 21104507 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2110459 + ... + 2110468.

It is an arithmetic number, because the mean of its divisors is an integer number (6331392).

Almost surely, 2^21104635 is an apocalyptic number.

21104635 is a deficient number, since it is larger than the sum of its proper divisors (4220933).

21104635 is an equidigital number, since it uses as much as digits as its factorization.

21104635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4220932.

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

The square root of 21104635 is about 4593.9781235874. The cubic root of 21104635 is about 276.3498809605.

Adding to 21104635 its reverse (53640112), we get a palindrome (74744747).

The spelling of 21104635 in words is "twenty-one million, one hundred four thousand, six hundred thirty-five".