31993728 has 192 divisors, whose sum is σ = 100796400. Its totient is φ = 8945664.

The previous prime is 31993723. The next prime is 31993771. The reversal of 31993728 is 82739913.

It is a tau number, because it is divible by the number of its divisors (192).

It is a self number, because there is not a number n which added to its sum of digits gives 31993728.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31993723) 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 23 ways as a sum of consecutive naturals, for example, 1103218 + ... + 1103246.

Almost surely, 2^31993728 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 31993728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50398200).

31993728 is an abundant number, since it is smaller than the sum of its proper divisors (68802672).

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

31993728 is a wasteful number, since it uses less digits than its factorization.

31993728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89 (or 64 counting only the distinct ones).

The product of its digits is 81648, while the sum is 42.

The square root of 31993728 is about 5656.2998506091. The cubic root of 31993728 is about 317.4594669979.

The spelling of 31993728 in words is "thirty-one million, nine hundred ninety-three thousand, seven hundred twenty-eight".