21256448 has 36 divisors (see below), whose sum is σ = 43439088. Its totient is φ = 10375680.

The previous prime is 21256447. The next prime is 21256457. The reversal of 21256448 is 84465212.

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

It is not an unprimeable number, because it can be changed into a prime (21256447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10043 + ... + 11973.

Almost surely, 2^21256448 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 21256448, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21719544).

21256448 is an abundant number, since it is smaller than the sum of its proper divisors (22182640).

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

21256448 is an equidigital number, since it uses as much as digits as its factorization.

21256448 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1990 (or 1976 counting only the distinct ones).

The product of its digits is 15360, while the sum is 32.

The square root of 21256448 is about 4610.4715593961. The cubic root of 21256448 is about 277.0109254684.

The spelling of 21256448 in words is "twenty-one million, two hundred fifty-six thousand, four hundred forty-eight".