21108683 has 4 divisors (see below), whose sum is σ = 21118968. Its totient is φ = 21098400.

The previous prime is 21108673. The next prime is 21108701. The reversal of 21108683 is 38680112.

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 is a cyclic number.

It is not a de Polignac number, because 21108683 - 2⁴ = 21108667 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21108673) 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, 893 + ... + 6558.

It is an arithmetic number, because the mean of its divisors is an integer number (5279742).

Almost surely, 2^21108683 is an apocalyptic number.

21108683 is a deficient number, since it is larger than the sum of its proper divisors (10285).

21108683 is an equidigital number, since it uses as much as digits as its factorization.

21108683 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10284.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 21108683 is about 4594.4186792237. The cubic root of 21108683 is about 276.3675483719.

Adding to 21108683 its reverse (38680112), we get a palindrome (59788795).

The spelling of 21108683 in words is "twenty-one million, one hundred eight thousand, six hundred eighty-three".