20565648 has 120 divisors (see below), whose sum is σ = 63138816. Its totient is φ = 6220800.

The previous prime is 20565637. The next prime is 20565659. The reversal of 20565648 is 84656502.

20565648 is a `hidden beast` number, since 2 + 0 + 5 + 6 + 5 + 648 = 666.

It is an interprime number because it is at equal distance from previous prime (20565637) and next prime (20565659).

It is a super-3 number, since 3×20565648³ (a number of 23 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 75753 + ... + 76023.

Almost surely, 2^20565648 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 20565648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31569408).

20565648 is an abundant number, since it is smaller than the sum of its proper divisors (42573168).

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

20565648 is a wasteful number, since it uses less digits than its factorization.

20565648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333 (or 324 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 20565648 is about 4534.9363832363. The cubic root of 20565648 is about 273.9770169154.

The spelling of 20565648 in words is "twenty million, five hundred sixty-five thousand, six hundred forty-eight".