20728188 has 54 divisors (see below), whose sum is σ = 56753424. Its totient is φ = 6376032.

The previous prime is 20728159. The next prime is 20728199. The reversal of 20728188 is 88182702.

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 pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4381 + ... + 7787.

Almost surely, 2^20728188 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 20728188, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28376712).

20728188 is an abundant number, since it is smaller than the sum of its proper divisors (36025236).

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

20728188 is a wasteful number, since it uses less digits than its factorization.

20728188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3443 (or 3425 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 20728188 is about 4552.8219820239. The cubic root of 20728188 is about 274.6969134640.

The spelling of 20728188 in words is "twenty million, seven hundred twenty-eight thousand, one hundred eighty-eight".