21240448 has 16 divisors (see below), whose sum is σ = 42315210. Its totient is φ = 10620160.

The previous prime is 21240433. The next prime is 21240511. The reversal of 21240448 is 84404212.

It can be written as a sum of positive squares in only one way, i.e., 20142144 + 1098304 = 4488^2 + 1048^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 82843 + ... + 83098.

Almost surely, 2^21240448 is an apocalyptic number.

It is an amenable number.

21240448 is a deficient number, since it is larger than the sum of its proper divisors (21074762).

21240448 is an equidigital number, since it uses as much as digits as its factorization.

21240448 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165955 (or 165943 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 25.

The square root of 21240448 is about 4608.7360523250. The cubic root of 21240448 is about 276.9414048015.

The spelling of 21240448 in words is "twenty-one million, two hundred forty thousand, four hundred forty-eight".