31728438 has 48 divisors (see below), whose sum is σ = 81110016. Its totient is φ = 8771760.

The previous prime is 31728427. The next prime is 31728451. The reversal of 31728438 is 83482713.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 156 + ... + 7967.

It is an arithmetic number, because the mean of its divisors is an integer number (1689792).

Almost surely, 2^31728438 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31728438, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40555008).

31728438 is an abundant number, since it is smaller than the sum of its proper divisors (49381578).

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

31728438 is a wasteful number, since it uses less digits than its factorization.

31728438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8169 (or 8166 counting only the distinct ones).

The product of its digits is 32256, while the sum is 36.

The square root of 31728438 is about 5632.8001917341. The cubic root of 31728438 is about 316.5795791298.

The spelling of 31728438 in words is "thirty-one million, seven hundred twenty-eight thousand, four hundred thirty-eight".