20891648 has 36 divisors (see below), whose sum is σ = 42190785. Its totient is φ = 10342400.

The previous prime is 20891639. The next prime is 20891669. The reversal of 20891648 is 84619802.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 14500864 + 6390784 = 3808^2 + 2528^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=3232.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 206798 + ... + 206898.

Almost surely, 2^20891648 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20891648

20891648 is an abundant number, since it is smaller than the sum of its proper divisors (21299137).

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

20891648 is an frugal number, since it uses more digits than its factorization.

20891648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224 (or 103 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 20891648 is about 4570.7382335898. The cubic root of 20891648 is about 275.4170992868.

The spelling of 20891648 in words is "twenty million, eight hundred ninety-one thousand, six hundred forty-eight".