1628038728 has 72 divisors (see below), whose sum is σ = 4683957330. Its totient is φ = 510750720.

The previous prime is 1628038723. The next prime is 1628038729. The reversal of 1628038728 is 8278308261.

It can be written as a sum of positive squares in 3 ways, for example, as 1547792964 + 80245764 = 39342^2 + 8958^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is not an unprimeable number, because it can be changed into a prime (1628038723) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 18313 + ... + 59928.

Almost surely, 2^1628038728 is an apocalyptic number.

1628038728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1628038728 is an abundant number, since it is smaller than the sum of its proper divisors (3055918602).

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

1628038728 is a wasteful number, since it uses less digits than its factorization.

1628038728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78287 (or 78263 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The square root of 1628038728 is about 40348.9619197322. The cubic root of 1628038728 is about 1176.3997148807.

The spelling of 1628038728 in words is "one billion, six hundred twenty-eight million, thirty-eight thousand, seven hundred twenty-eight".