20647656 has 64 divisors (see below), whose sum is σ = 60739200. Its totient is φ = 6476544.

The previous prime is 20647651. The next prime is 20647663. The reversal of 20647656 is 65674602.

20647656 is a `hidden beast` number, since 2 + 0 + 647 + 6 + 5 + 6 = 666.

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

It is a self number, because there is not a number n which added to its sum of digits gives 20647656.

It is not an unprimeable number, because it can be changed into a prime (20647651) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 861 + ... + 6483.

It is an arithmetic number, because the mean of its divisors is an integer number (949050).

Almost surely, 2^20647656 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 20647656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30369600).

20647656 is an abundant number, since it is smaller than the sum of its proper divisors (40091544).

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

20647656 is a wasteful number, since it uses less digits than its factorization.

20647656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5655 (or 5645 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The square root of 20647656 is about 4543.9691900364. The cubic root of 20647656 is about 274.3407060498.

The spelling of 20647656 in words is "twenty million, six hundred forty-seven thousand, six hundred fifty-six".