20843728 has 40 divisors (see below), whose sum is σ = 41941512. Its totient is φ = 10027008.

The previous prime is 20843723. The next prime is 20843731. The reversal of 20843728 is 82734802.

It can be written as a sum of positive squares in 4 ways, for example, as 14653584 + 6190144 = 3828^2 + 2488^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20843693 and 20843702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20843723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80976 + ... + 81232.

Almost surely, 2^20843728 is an apocalyptic number.

It is an amenable number.

20843728 is an abundant number, since it is smaller than the sum of its proper divisors (21097784).

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

20843728 is a wasteful number, since it uses less digits than its factorization.

20843728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439 (or 433 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 34.

The square root of 20843728 is about 4565.4931825598. The cubic root of 20843728 is about 275.2063597097.

It can be divided in two parts, 208437 and 28, that multiplied together give a triangular number (5836236 = T₃₄₁₆).

The spelling of 20843728 in words is "twenty million, eight hundred forty-three thousand, seven hundred twenty-eight".