21283218 has 48 divisors (see below), whose sum is σ = 53273376. Its totient is φ = 6069120.

The previous prime is 21283217. The next prime is 21283243. The reversal of 21283218 is 81238212.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21283191 and 21283200.

It is not an unprimeable number, because it can be changed into a prime (21283217) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 205 + ... + 6527.

It is an arithmetic number, because the mean of its divisors is an integer number (1109862).

Almost surely, 2^21283218 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21283218, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26636688).

21283218 is an abundant number, since it is smaller than the sum of its proper divisors (31990158).

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

21283218 is a wasteful number, since it uses less digits than its factorization.

21283218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6359 (or 6356 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 21283218 is about 4613.3738196682. The cubic root of 21283218 is about 277.1271642623.

The spelling of 21283218 in words is "twenty-one million, two hundred eighty-three thousand, two hundred eighteen".