20728428 has 48 divisors (see below), whose sum is σ = 57684480. Its totient is φ = 5664384.

The previous prime is 20728427. The next prime is 20728439. The reversal of 20728428 is 82482702.

It is not an unprimeable number, because it can be changed into a prime (20728427) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3433 + ... + 7296.

It is an arithmetic number, because the mean of its divisors is an integer number (1201760).

Almost surely, 2^20728428 is an apocalyptic number.

20728428 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

20728428 is an abundant number, since it is smaller than the sum of its proper divisors (36956052).

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

20728428 is a wasteful number, since it uses less digits than its factorization.

20728428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10766 (or 10764 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 33.

The square root of 20728428 is about 4552.8483392268. The cubic root of 20728428 is about 274.6979736468.

The spelling of 20728428 in words is "twenty million, seven hundred twenty-eight thousand, four hundred twenty-eight".