31381328 has 80 divisors (see below), whose sum is σ = 70114560. Its totient is φ = 13478400.

The previous prime is 31381307. The next prime is 31381349. The reversal of 31381328 is 82318313.

It is an interprime number because it is at equal distance from previous prime (31381307) and next prime (31381349).

It is a zygodrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 31381328.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 397193 + ... + 397271.

It is an arithmetic number, because the mean of its divisors is an integer number (876432).

Almost surely, 2^31381328 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 31381328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35057280).

31381328 is an abundant number, since it is smaller than the sum of its proper divisors (38733232).

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

31381328 is a wasteful number, since it uses less digits than its factorization.

31381328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196 (or 190 counting only the distinct ones).

The product of its digits is 3456, while the sum is 29.

The square root of 31381328 is about 5601.9039620472. The cubic root of 31381328 is about 315.4208802485.

The spelling of 31381328 in words is "thirty-one million, three hundred eighty-one thousand, three hundred twenty-eight".