31728823 has 6 divisors (see below), whose sum is σ = 36909096. Its totient is φ = 27196092.

The previous prime is 31728811. The next prime is 31728857. The reversal of 31728823 is 32882713.

It is not a de Polignac number, because 31728823 - 2⁹ = 31728311 is a prime.

It is a super-3 number, since 3×31728823³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31728863) 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 in 5 ways as a sum of consecutive naturals, for example, 323715 + ... + 323812.

It is an arithmetic number, because the mean of its divisors is an integer number (6151516).

Almost surely, 2^31728823 is an apocalyptic number.

31728823 is a deficient number, since it is larger than the sum of its proper divisors (5180273).

31728823 is an equidigital number, since it uses as much as digits as its factorization.

31728823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 647541 (or 647534 counting only the distinct ones).

The product of its digits is 16128, while the sum is 34.

The square root of 31728823 is about 5632.8343664624. The cubic root of 31728823 is about 316.5808596073.

The spelling of 31728823 in words is "thirty-one million, seven hundred twenty-eight thousand, eight hundred twenty-three".