21204323 has 8 divisors (see below), whose sum is σ = 25509120. Its totient is φ = 17218440.

The previous prime is 21204251. The next prime is 21204329. The reversal of 21204323 is 32340212.

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

It is a cyclic number.

It is not a de Polignac number, because 21204323 - 2⁸ = 21204067 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21204329) 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, 79583 + ... + 79848.

It is an arithmetic number, because the mean of its divisors is an integer number (3188640).

Almost surely, 2^21204323 is an apocalyptic number.

21204323 is a deficient number, since it is larger than the sum of its proper divisors (4304797).

21204323 is a wasteful number, since it uses less digits than its factorization.

21204323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159457.

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 21204323 is about 4604.8151971605. The cubic root of 21204323 is about 276.7843116714.

Adding to 21204323 its reverse (32340212), we get a palindrome (53544535).

The spelling of 21204323 in words is "twenty-one million, two hundred four thousand, three hundred twenty-three".