21804838 has 8 divisors (see below), whose sum is σ = 35680680. Its totient is φ = 9911280.

The previous prime is 21804833. The next prime is 21804857. The reversal of 21804838 is 83840812.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21804833) 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 3 ways as a sum of consecutive naturals, for example, 495543 + ... + 495586.

It is an arithmetic number, because the mean of its divisors is an integer number (4460085).

Almost surely, 2^21804838 is an apocalyptic number.

21804838 is a deficient number, since it is larger than the sum of its proper divisors (13875842).

21804838 is a wasteful number, since it uses less digits than its factorization.

21804838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 991142.

The product of its (nonzero) digits is 12288, while the sum is 34.

The square root of 21804838 is about 4669.5650761072. The cubic root of 21804838 is about 279.3729078280.

The spelling of 21804838 in words is "twenty-one million, eight hundred four thousand, eight hundred thirty-eight".