31728723 has 16 divisors (see below), whose sum is σ = 46309536. Its totient is φ = 19203840.

The previous prime is 31728679. The next prime is 31728769. The reversal of 31728723 is 32782713.

It is not a de Polignac number, because 31728723 - 2⁸ = 31728467 is a prime.

It is a super-3 number, since 3×31728723³ (a number of 23 digits) contains 333 as substring.

31728723 is a modest number, since divided by 8723 gives 3172 as remainder.

It is not an unprimeable number, because it can be changed into a prime (31728773) 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 15 ways as a sum of consecutive naturals, for example, 4290 + ... + 9047.

It is an arithmetic number, because the mean of its divisors is an integer number (2894346).

Almost surely, 2^31728723 is an apocalyptic number.

31728723 is a deficient number, since it is larger than the sum of its proper divisors (14580813).

31728723 is a wasteful number, since it uses less digits than its factorization.

31728723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13414.

The product of its digits is 14112, while the sum is 33.

The square root of 31728723 is about 5632.8254899295. The cubic root of 31728723 is about 316.5805270167.

The spelling of 31728723 in words is "thirty-one million, seven hundred twenty-eight thousand, seven hundred twenty-three".