31728042 has 24 divisors (see below), whose sum is σ = 69107844. Its totient is φ = 10520064.

The previous prime is 31728041. The next prime is 31728071. The reversal of 31728042 is 24082713.

It can be written as a sum of positive squares in 2 ways, for example, as 31708161 + 19881 = 5631^2 + 141^2 .

It is a junction number, because it is equal to n+sod(n) for n = 31727997 and 31728015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31728041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1093 + ... + 8040.

Almost surely, 2^31728042 is an apocalyptic number.

31728042 is an abundant number, since it is smaller than the sum of its proper divisors (37379802).

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

31728042 is a wasteful number, since it uses less digits than its factorization.

31728042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9334 (or 9331 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 31728042 is about 5632.7650403687. The cubic root of 31728042 is about 316.5782620565.

The spelling of 31728042 in words is "thirty-one million, seven hundred twenty-eight thousand, forty-two".