31830728 has 8 divisors (see below), whose sum is σ = 59682630. Its totient is φ = 15915360.

The previous prime is 31830727. The next prime is 31830779. The reversal of 31830728 is 82703813.

It can be written as a sum of positive squares in only one way, i.e., 22108804 + 9721924 = 4702^2 + 3118^2 .

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 = 31830694 and 31830703.

It is not an unprimeable number, because it can be changed into a prime (31830727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1989413 + ... + 1989428.

Almost surely, 2^31830728 is an apocalyptic number.

It is an amenable number.

31830728 is a deficient number, since it is larger than the sum of its proper divisors (27851902).

31830728 is a wasteful number, since it uses less digits than its factorization.

31830728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3978847 (or 3978843 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 31830728 is about 5641.8727387278. The cubic root of 31830728 is about 316.9194234396.

The spelling of 31830728 in words is "thirty-one million, eight hundred thirty thousand, seven hundred twenty-eight".