20864736 has 192 divisors, whose sum is σ = 67737600. Its totient is φ = 6220800.

The previous prime is 20864731. The next prime is 20864737. The reversal of 20864736 is 63746802.

20864736 is a `hidden beast` number, since 2 + 0 + 8 + 647 + 3 + 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 20864736.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20864731) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 508876 + ... + 508916.

It is an arithmetic number, because the mean of its divisors is an integer number (352800).

Almost surely, 2^20864736 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 20864736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33868800).

20864736 is an abundant number, since it is smaller than the sum of its proper divisors (46872864).

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

20864736 is a wasteful number, since it uses less digits than its factorization.

20864736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110 (or 96 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The square root of 20864736 is about 4567.7933403340. The cubic root of 20864736 is about 275.2987870964.

The spelling of 20864736 in words is "twenty million, eight hundred sixty-four thousand, seven hundred thirty-six".