21283839 has 18 divisors (see below), whose sum is σ = 31499520. Its totient is φ = 13848408.

The previous prime is 21283777. The next prime is 21283841. The reversal of 21283839 is 93838212.

It is a happy number.

It is not a de Polignac number, because 21283839 - 2⁸ = 21283583 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21283859) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 16002 + ... + 17280.

Almost surely, 2^21283839 is an apocalyptic number.

21283839 is a deficient number, since it is larger than the sum of its proper divisors (10215681).

21283839 is a wasteful number, since it uses less digits than its factorization.

21283839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1371 (or 1325 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 21283839 is about 4613.4411234999. The cubic root of 21283839 is about 277.1298595674.

It can be divided in two parts, 21283 and 839, that added together give a palindrome (22122).

The spelling of 21283839 in words is "twenty-one million, two hundred eighty-three thousand, eight hundred thirty-nine".