21649648 has 20 divisors (see below), whose sum is σ = 42109408. Its totient is φ = 10782720.

The previous prime is 21649627. The next prime is 21649651. The reversal of 21649648 is 84694612.

It is a plaindrome in base 11.

It is a self number, because there is not a number n which added to its sum of digits gives 21649648.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1840 + ... + 6832.

Almost surely, 2^21649648 is an apocalyptic number.

It is an amenable number.

21649648 is a deficient number, since it is larger than the sum of its proper divisors (20459760).

21649648 is a wasteful number, since it uses less digits than its factorization.

21649648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5272 (or 5266 counting only the distinct ones).

The product of its digits is 82944, while the sum is 40.

The square root of 21649648 is about 4652.9182240826. The cubic root of 21649648 is about 278.7085423004.

The spelling of 21649648 in words is "twenty-one million, six hundred forty-nine thousand, six hundred forty-eight".