21006448 has 20 divisors (see below), whose sum is σ = 41369128. Its totient is φ = 10330560.

The previous prime is 21006439. The next prime is 21006451. The reversal of 21006448 is 84460012.

It is a congruent number.

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 in 3 ways as a sum of consecutive naturals, for example, 9786 + ... + 11737.

Almost surely, 2^21006448 is an apocalyptic number.

It is an amenable number.

21006448 is a deficient number, since it is larger than the sum of its proper divisors (20362680).

21006448 is a wasteful number, since it uses less digits than its factorization.

21006448 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21592 (or 21586 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 21006448 is about 4583.2791754376. The cubic root of 21006448 is about 275.9206521185.

The spelling of 21006448 in words is "twenty-one million, six thousand, four hundred forty-eight".