31728031 has 2 divisors, whose sum is σ = 31728032. Its totient is φ = 31728030.

The previous prime is 31728013. The next prime is 31728041. The reversal of 31728031 is 13082713.

Together with previous prime (31728013) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31728031 - 2⁷ = 31727903 is a prime.

It is a super-2 number, since 2×31728031² = 2013335902273922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31727987 and 31728005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31728041) 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, 15864015 + 15864016.

It is an arithmetic number, because the mean of its divisors is an integer number (15864016).

Almost surely, 2^31728031 is an apocalyptic number.

31728031 is a deficient number, since it is larger than the sum of its proper divisors (1).

31728031 is an equidigital number, since it uses as much as digits as its factorization.

31728031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 31728031 is about 5632.7640639388. The cubic root of 31728031 is about 316.5782254710.

The spelling of 31728031 in words is "thirty-one million, seven hundred twenty-eight thousand, thirty-one".