20728408 has 16 divisors (see below), whose sum is σ = 39770280. Its totient is φ = 10123008.

The previous prime is 20728403. The next prime is 20728427. The reversal of 20728408 is 80482702.

It is a self number, because there is not a number n which added to its sum of digits gives 20728408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728403) 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 3 ways as a sum of consecutive naturals, for example, 29785 + ... + 30472.

Almost surely, 2^20728408 is an apocalyptic number.

It is an amenable number.

20728408 is a deficient number, since it is larger than the sum of its proper divisors (19041872).

20728408 is a wasteful number, since it uses less digits than its factorization.

20728408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60306 (or 60302 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 31.

The square root of 20728408 is about 4552.8461427990. The cubic root of 20728408 is about 274.6978852985.

The spelling of 20728408 in words is "twenty million, seven hundred twenty-eight thousand, four hundred eight".