21061648 has 20 divisors (see below), whose sum is σ = 42124288. Its totient is φ = 10190880.

The previous prime is 21061639. The next prime is 21061669. The reversal of 21061648 is 84616012.

21061648 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20736 + ... + 21727.

Almost surely, 2^21061648 is an apocalyptic number.

It is an amenable number.

21061648 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21061648 is a wasteful number, since it uses less digits than its factorization.

21061648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42502 (or 42496 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 21061648 is about 4589.2971139380. The cubic root of 21061648 is about 276.1621255689.

The spelling of 21061648 in words is "twenty-one million, sixty-one thousand, six hundred forty-eight".