21204311 has 8 divisors (see below), whose sum is σ = 21638400. Its totient is φ = 20774520.

The previous prime is 21204251. The next prime is 21204329. The reversal of 21204311 is 11340212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21204311 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201311) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 10016 + ... + 11946.

It is an arithmetic number, because the mean of its divisors is an integer number (2704800).

Almost surely, 2^21204311 is an apocalyptic number.

21204311 is a deficient number, since it is larger than the sum of its proper divisors (434089).

21204311 is a wasteful number, since it uses less digits than its factorization.

21204311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2149.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21204311 is about 4604.8138941764. The cubic root of 21204311 is about 276.7842594586.

Adding to 21204311 its reverse (11340212), we get a palindrome (32544523).

The spelling of 21204311 in words is "twenty-one million, two hundred four thousand, three hundred eleven".