31325728 has 48 divisors (see below), whose sum is σ = 71184960. Its totient is φ = 13291776.

The previous prime is 31325711. The next prime is 31325729. The reversal of 31325728 is 82752313.

It is a self number, because there is not a number n which added to its sum of digits gives 31325728.

It is not an unprimeable number, because it can be changed into a prime (31325729) 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, 23775 + ... + 25057.

It is an arithmetic number, because the mean of its divisors is an integer number (1483020).

Almost surely, 2^31325728 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 31325728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35592480).

31325728 is an abundant number, since it is smaller than the sum of its proper divisors (39859232).

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

31325728 is a wasteful number, since it uses less digits than its factorization.

31325728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1409 (or 1401 counting only the distinct ones).

The product of its digits is 10080, while the sum is 31.

The square root of 31325728 is about 5596.9391635071. The cubic root of 31325728 is about 315.2344873668.

The spelling of 31325728 in words is "thirty-one million, three hundred twenty-five thousand, seven hundred twenty-eight".