21409648 has 20 divisors (see below), whose sum is σ = 44672488. Its totient is φ = 9881280.

The previous prime is 21409631. The next prime is 21409669. The reversal of 21409648 is 84690412.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51258 + ... + 51673.

Almost surely, 2^21409648 is an apocalyptic number.

It is an amenable number.

21409648 is an abundant number, since it is smaller than the sum of its proper divisors (23262840).

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

21409648 is a wasteful number, since it uses less digits than its factorization.

21409648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102952 (or 102946 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 21409648 is about 4627.0560835157. The cubic root of 21409648 is about 277.6748263935.

The spelling of 21409648 in words is "twenty-one million, four hundred nine thousand, six hundred forty-eight".