3128731785 has 32 divisors (see below), whose sum is σ = 5653388160. Its totient is φ = 1641297600.

The previous prime is 3128731783. The next prime is 3128731813. The reversal of 3128731785 is 5871378213.

3128731785 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 3128731785 - 2¹ = 3128731783 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 3128731785.

It is not an unprimeable number, because it can be changed into a prime (3128731783) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 181731 + ... + 198200.

It is an arithmetic number, because the mean of its divisors is an integer number (176668380).

Almost surely, 2^3128731785 is an apocalyptic number.

It is an amenable number.

3128731785 is a deficient number, since it is larger than the sum of its proper divisors (2524656375).

3128731785 is a wasteful number, since it uses less digits than its factorization.

3128731785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380006 (or 380000 counting only the distinct ones).

The product of its digits is 282240, while the sum is 45.

The square root of 3128731785 is about 55935.0675783984. The cubic root of 3128731785 is about 1462.5906005674.

The spelling of 3128731785 in words is "three billion, one hundred twenty-eight million, seven hundred thirty-one thousand, seven hundred eighty-five".