21284438 has 16 divisors (see below), whose sum is σ = 36777984. Its totient is φ = 9049320.

The previous prime is 21284423. The next prime is 21284489. The reversal of 21284438 is 83448212.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4208 + ... + 7763.

It is an arithmetic number, because the mean of its divisors is an integer number (2298624).

Almost surely, 2^21284438 is an apocalyptic number.

21284438 is a deficient number, since it is larger than the sum of its proper divisors (15493546).

21284438 is a wasteful number, since it uses less digits than its factorization.

21284438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12107.

The product of its digits is 12288, while the sum is 32.

The square root of 21284438 is about 4613.5060420465. The cubic root of 21284438 is about 277.1324593369.

The spelling of 21284438 in words is "twenty-one million, two hundred eighty-four thousand, four hundred thirty-eight".