21604603 has 4 divisors (see below), whose sum is σ = 22875480. Its totient is φ = 20333728.

The previous prime is 21604601. The next prime is 21604621. The reversal of 21604603 is 30640612.

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 21604603 - 2¹ = 21604601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21604601) 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, 635413 + ... + 635446.

It is an arithmetic number, because the mean of its divisors is an integer number (5718870).

Almost surely, 2^21604603 is an apocalyptic number.

21604603 is a deficient number, since it is larger than the sum of its proper divisors (1270877).

21604603 is a wasteful number, since it uses less digits than its factorization.

21604603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1270876.

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 21604603 is about 4648.0751930235. The cubic root of 21604603 is about 278.5151112352.

The spelling of 21604603 in words is "twenty-one million, six hundred four thousand, six hundred three".