21284838 has 12 divisors (see below), whose sum is σ = 46117188. Its totient is φ = 7094940.

The previous prime is 21284801. The next prime is 21284839. The reversal of 21284838 is 83848212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21284839) 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 5 ways as a sum of consecutive naturals, for example, 591228 + ... + 591263.

It is an arithmetic number, because the mean of its divisors is an integer number (3843099).

Almost surely, 2^21284838 is an apocalyptic number.

21284838 is an abundant number, since it is smaller than the sum of its proper divisors (24832350).

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

21284838 is a wasteful number, since it uses less digits than its factorization.

21284838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1182499 (or 1182496 counting only the distinct ones).

The product of its digits is 24576, while the sum is 36.

The square root of 21284838 is about 4613.5493928211. The cubic root of 21284838 is about 277.1341953829.

It can be divided in two parts, 21284 and 838, that added together give a palindrome (22122).

The spelling of 21284838 in words is "twenty-one million, two hundred eighty-four thousand, eight hundred thirty-eight".