21204318 has 8 divisors (see below), whose sum is σ = 42408648. Its totient is φ = 7068104.

The previous prime is 21204251. The next prime is 21204329. The reversal of 21204318 is 81340212.

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

21204318 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 21204294 and 21204303.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1767021 + ... + 1767032.

It is an arithmetic number, because the mean of its divisors is an integer number (5301081).

Almost surely, 2^21204318 is an apocalyptic number.

21204318 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21204318 is a wasteful number, since it uses less digits than its factorization.

21204318 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3534058.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21204318 is about 4604.8146542505. The cubic root of 21204318 is about 276.7842899161.

The spelling of 21204318 in words is "twenty-one million, two hundred four thousand, three hundred eighteen".