31681044 has 60 divisors (see below), whose sum is σ = 83354964. Its totient is φ = 10492416.

The previous prime is 31681043. The next prime is 31681057. The reversal of 31681044 is 44018613.

It can be written as a sum of positive squares in 2 ways, for example, as 8928144 + 22752900 = 2988^2 + 4770^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 31680999 and 31681017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31681043) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 89572 + ... + 89924.

Almost surely, 2^31681044 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 31681044, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41677482).

31681044 is an abundant number, since it is smaller than the sum of its proper divisors (51673920).

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

31681044 is a wasteful number, since it uses less digits than its factorization.

31681044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 646 (or 635 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 31681044 is about 5628.5916533357. The cubic root of 31681044 is about 316.4218715086.

Adding to 31681044 its reverse (44018613), we get a palindrome (75699657).

The spelling of 31681044 in words is "thirty-one million, six hundred eighty-one thousand, forty-four".