21256248 has 64 divisors (see below), whose sum is σ = 57687840. Its totient is φ = 6488064.

The previous prime is 21256247. The next prime is 21256253. The reversal of 21256248 is 84265212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21256247) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60040 + ... + 60392.

Almost surely, 2^21256248 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 21256248, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28843920).

21256248 is an abundant number, since it is smaller than the sum of its proper divisors (36431592).

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

21256248 is a wasteful number, since it uses less digits than its factorization.

21256248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 568 (or 564 counting only the distinct ones).

The product of its digits is 7680, while the sum is 30.

The square root of 21256248 is about 4610.4498695897. The cubic root of 21256248 is about 277.0100566755.

The spelling of 21256248 in words is "twenty-one million, two hundred fifty-six thousand, two hundred forty-eight".