31289328 has 100 divisors (see below), whose sum is σ = 103527600. Its totient is φ = 8937216.

The previous prime is 31289327. The next prime is 31289339. The reversal of 31289328 is 82398213.

It is a happy number.

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

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 31289292 and 31289301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31289327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 7348 + ... + 10796.

It is an arithmetic number, because the mean of its divisors is an integer number (1035276).

Almost surely, 2^31289328 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 31289328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51763800).

31289328 is an abundant number, since it is smaller than the sum of its proper divisors (72238272).

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

31289328 is a wasteful number, since it uses less digits than its factorization.

31289328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3476 (or 3461 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 31289328 is about 5593.6864409797. The cubic root of 31289328 is about 315.1123408826.

The spelling of 31289328 in words is "thirty-one million, two hundred eighty-nine thousand, three hundred twenty-eight".