21283238 has 4 divisors (see below), whose sum is σ = 31924860. Its totient is φ = 10641618.

The previous prime is 21283217. The next prime is 21283243. The reversal of 21283238 is 83238212.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21283238.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5320808 + ... + 5320811.

It is an arithmetic number, because the mean of its divisors is an integer number (7981215).

Almost surely, 2^21283238 is an apocalyptic number.

21283238 is a deficient number, since it is larger than the sum of its proper divisors (10641622).

21283238 is a wasteful number, since it uses less digits than its factorization.

21283238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10641621.

The product of its digits is 4608, while the sum is 29.

The square root of 21283238 is about 4613.3759872787. The cubic root of 21283238 is about 277.1272510685.

The spelling of 21283238 in words is "twenty-one million, two hundred eighty-three thousand, two hundred thirty-eight".