21604227 has 8 divisors (see below), whose sum is σ = 28955664. Its totient is φ = 14327808.

The previous prime is 21604223. The next prime is 21604243. The reversal of 21604227 is 72240612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21604227 - 2² = 21604223 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21604197 and 21604206.

It is not an unprimeable number, because it can be changed into a prime (21604223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18078 + ... + 19235.

It is an arithmetic number, because the mean of its divisors is an integer number (3619458).

Almost surely, 2^21604227 is an apocalyptic number.

21604227 is a deficient number, since it is larger than the sum of its proper divisors (7351437).

21604227 is a wasteful number, since it uses less digits than its factorization.

21604227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37509.

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 21604227 is about 4648.0347459975. The cubic root of 21604227 is about 278.5134954948.

Adding to 21604227 its reverse (72240612), we get a palindrome (93844839).

The spelling of 21604227 in words is "twenty-one million, six hundred four thousand, two hundred twenty-seven".