31906728 has 192 divisors, whose sum is σ = 106704000. Its totient is φ = 8418816.

The previous prime is 31906723. The next prime is 31906729. The reversal of 31906728 is 82760913.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 31906692 and 31906701.

It is not an unprimeable number, because it can be changed into a prime (31906723) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 540763 + ... + 540821.

It is an arithmetic number, because the mean of its divisors is an integer number (555750).

Almost surely, 2^31906728 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 31906728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53352000).

31906728 is an abundant number, since it is smaller than the sum of its proper divisors (74797272).

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

31906728 is a wasteful number, since it uses less digits than its factorization.

31906728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144 (or 137 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 31906728 is about 5648.6040753446. The cubic root of 31906728 is about 317.1714517332.

The spelling of 31906728 in words is "thirty-one million, nine hundred six thousand, seven hundred twenty-eight".