2118306728 has 8 divisors (see below), whose sum is σ = 3971825130. Its totient is φ = 1059153360.

The previous prime is 2118306727. The next prime is 2118306731. The reversal of 2118306728 is 8276038112.

It can be written as a sum of positive squares in only one way, i.e., 1648197604 + 470109124 = 40598^2 + 21682^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 2118306691 and 2118306700.

It is not an unprimeable number, because it can be changed into a prime (2118306727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 132394163 + ... + 132394178.

Almost surely, 2^2118306728 is an apocalyptic number.

It is an amenable number.

2118306728 is a deficient number, since it is larger than the sum of its proper divisors (1853518402).

2118306728 is a wasteful number, since it uses less digits than its factorization.

2118306728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 264788347 (or 264788343 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 2118306728 is about 46025.0663008757. The cubic root of 2118306728 is about 1284.2895491902.

The spelling of 2118306728 in words is "two billion, one hundred eighteen million, three hundred six thousand, seven hundred twenty-eight".