31728224 has 48 divisors (see below), whose sum is σ = 71124480. Its totient is φ = 13791360.

The previous prime is 31728211. The next prime is 31728227. The reversal of 31728224 is 42282713.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31728227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6137 + ... + 10055.

It is an arithmetic number, because the mean of its divisors is an integer number (1481760).

Almost surely, 2^31728224 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31728224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35562240).

31728224 is an abundant number, since it is smaller than the sum of its proper divisors (39396256).

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

31728224 is a wasteful number, since it uses less digits than its factorization.

31728224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3963 (or 3955 counting only the distinct ones).

The product of its digits is 5376, while the sum is 29.

The square root of 31728224 is about 5632.7811958215. The cubic root of 31728224 is about 316.5788673795.

The spelling of 31728224 in words is "thirty-one million, seven hundred twenty-eight thousand, two hundred twenty-four".