21285248 has 32 divisors (see below), whose sum is σ = 42687000. Its totient is φ = 10571776.

The previous prime is 21285247. The next prime is 21285269. The reversal of 21285248 is 84258212.

It is a tau number, because it is divible by the number of its divisors (32).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21285247) 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, 22448 + ... + 23376.

Almost surely, 2^21285248 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21285248, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21343500).

21285248 is an abundant number, since it is smaller than the sum of its proper divisors (21401752).

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

21285248 is an equidigital number, since it uses as much as digits as its factorization.

21285248 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1122 (or 1110 counting only the distinct ones).

The product of its digits is 10240, while the sum is 32.

The square root of 21285248 is about 4613.5938269423. The cubic root of 21285248 is about 277.1359748075.

The spelling of 21285248 in words is "twenty-one million, two hundred eighty-five thousand, two hundred forty-eight".