20728618 has 16 divisors (see below), whose sum is σ = 31837536. Its totient is φ = 10118160.

The previous prime is 20728597. The next prime is 20728619. The reversal of 20728618 is 81682702.

It is not an unprimeable number, because it can be changed into a prime (20728619) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29653 + ... + 30343.

It is an arithmetic number, because the mean of its divisors is an integer number (1989846).

Almost surely, 2^20728618 is an apocalyptic number.

20728618 is a deficient number, since it is larger than the sum of its proper divisors (11108918).

20728618 is a wasteful number, since it uses less digits than its factorization.

20728618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1029.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 20728618 is about 4552.8692052375. The cubic root of 20728618 is about 274.6988129524.

The spelling of 20728618 in words is "twenty million, seven hundred twenty-eight thousand, six hundred eighteen".