31330440 has 96 divisors (see below), whose sum is σ = 105370200. Its totient is φ = 8064000.

The previous prime is 31330433. The next prime is 31330441. The reversal of 31330440 is 4403313.

It can be written as a sum of positive squares in 4 ways, for example, as 25826724 + 5503716 = 5082^2 + 2346^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (31330441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8940 + ... + 11940.

Almost surely, 2^31330440 is an apocalyptic number.

31330440 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31330440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52685100).

31330440 is an abundant number, since it is smaller than the sum of its proper divisors (74039760).

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

31330440 is a wasteful number, since it uses less digits than its factorization.

31330440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3047 (or 3040 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 18.

The square root of 31330440 is about 5597.3600920434. The cubic root of 31330440 is about 315.2502923779.

Adding to 31330440 its reverse (4403313), we get a palindrome (35733753).

The spelling of 31330440 in words is "thirty-one million, three hundred thirty thousand, four hundred forty".