31731028 has 36 divisors (see below), whose sum is σ = 65300340. Its totient is φ = 13450752.

The previous prime is 31731023. The next prime is 31731031. The reversal of 31731028 is 82013713.

It can be written as a sum of positive squares in 2 ways, for example, as 15586704 + 16144324 = 3948^2 + 4018^2 .

It is a plaindrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 31730993 and 31731011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31731023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18178 + ... + 19846.

Almost surely, 2^31731028 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 31731028, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32650170).

31731028 is an abundant number, since it is smaller than the sum of its proper divisors (33569312).

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

31731028 is a wasteful number, since it uses less digits than its factorization.

31731028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1784 (or 1775 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 31731028 is about 5633.0300904575. The cubic root of 31731028 is about 316.5881930511.

The spelling of 31731028 in words is "thirty-one million, seven hundred thirty-one thousand, twenty-eight".