31728732 has 72 divisors (see below), whose sum is σ = 89948544. Its totient is φ = 8525568.

The previous prime is 31728679. The next prime is 31728769. The reversal of 31728732 is 23782713.

It is a junction number, because it is equal to n+sod(n) for n = 31728693 and 31728702.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 23623 + ... + 24929.

Almost surely, 2^31728732 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 31728732, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44974272).

31728732 is an abundant number, since it is smaller than the sum of its proper divisors (58219812).

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

31728732 is a wasteful number, since it uses less digits than its factorization.

31728732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1355 (or 1336 counting only the distinct ones).

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

The square root of 31728732 is about 5632.8262888181. The cubic root of 31728732 is about 316.5805569499.

The spelling of 31728732 in words is "thirty-one million, seven hundred twenty-eight thousand, seven hundred thirty-two".