21724603 has 4 divisors (see below), whose sum is σ = 21735000. Its totient is φ = 21714208.

The previous prime is 21724553. The next prime is 21724607. The reversal of 21724603 is 30642712.

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 21724603 - 2⁹ = 21724091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21724607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 853 + ... + 6646.

It is an arithmetic number, because the mean of its divisors is an integer number (5433750).

Almost surely, 2^21724603 is an apocalyptic number.

21724603 is a deficient number, since it is larger than the sum of its proper divisors (10397).

21724603 is an equidigital number, since it uses as much as digits as its factorization.

21724603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10396.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 21724603 is about 4660.9658870238. The cubic root of 21724603 is about 279.0298182867.

The spelling of 21724603 in words is "twenty-one million, seven hundred twenty-four thousand, six hundred three".