20618728 has 16 divisors (see below), whose sum is σ = 41634180. Its totient is φ = 9516288.

The previous prime is 20618713. The next prime is 20618729. The reversal of 20618728 is 82781602.

It can be written as a sum of positive squares in 2 ways, for example, as 19731364 + 887364 = 4442^2 + 942^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20618693 and 20618702.

It is not an unprimeable number, because it can be changed into a prime (20618729) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 99025 + ... + 99232.

Almost surely, 2^20618728 is an apocalyptic number.

It is an amenable number.

20618728 is an abundant number, since it is smaller than the sum of its proper divisors (21015452).

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

20618728 is a wasteful number, since it uses less digits than its factorization.

20618728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198276 (or 198272 counting only the distinct ones).

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

The square root of 20618728 is about 4540.7849541682. The cubic root of 20618728 is about 274.2125262525.

The spelling of 20618728 in words is "twenty million, six hundred eighteen thousand, seven hundred twenty-eight".