21283216 has 20 divisors (see below), whose sum is σ = 42659100. Its totient is φ = 10274432.

The previous prime is 21283181. The next prime is 21283217. The reversal of 21283216 is 61238212.

It can be written as a sum of positive squares in 2 ways, for example, as 12988816 + 8294400 = 3604^2 + 2880^2 .

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 3 ways as a sum of consecutive naturals, for example, 22471 + ... + 23398.

It is an arithmetic number, because the mean of its divisors is an integer number (2132955).

Almost surely, 2^21283216 is an apocalyptic number.

It is an amenable number.

21283216 is an abundant number, since it is smaller than the sum of its proper divisors (21375884).

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

21283216 is a wasteful number, since it uses less digits than its factorization.

21283216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45906 (or 45900 counting only the distinct ones).

The product of its digits is 1152, while the sum is 25.

The square root of 21283216 is about 4613.3736029071. The cubic root of 21283216 is about 277.1271555817.

The spelling of 21283216 in words is "twenty-one million, two hundred eighty-three thousand, two hundred sixteen".