21286238 has 8 divisors (see below), whose sum is σ = 32162832. Its totient is φ = 10565296.

The previous prime is 21286229. The next prime is 21286241. The reversal of 21286238 is 83268212.

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

It is a Curzon number.

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, 38570 + ... + 39117.

It is an arithmetic number, because the mean of its divisors is an integer number (4020354).

Almost surely, 2^21286238 is an apocalyptic number.

21286238 is a deficient number, since it is larger than the sum of its proper divisors (10876594).

21286238 is a wasteful number, since it uses less digits than its factorization.

21286238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77826.

The product of its digits is 9216, while the sum is 32.

The square root of 21286238 is about 4613.7011173244. The cubic root of 21286238 is about 277.1402713726.

The spelling of 21286238 in words is "twenty-one million, two hundred eighty-six thousand, two hundred thirty-eight".