31125240 has 96 divisors (see below), whose sum is σ = 104457600. Its totient is φ = 8029440.

The previous prime is 31125239. The next prime is 31125247. The reversal of 31125240 is 4252113.

It is a Cunningham number, because it is equal to 5579²-1.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31125247) 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 23 ways as a sum of consecutive naturals, for example, 9766 + ... + 12554.

It is an arithmetic number, because the mean of its divisors is an integer number (1088100).

Almost surely, 2^31125240 is an apocalyptic number.

31125240 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 31125240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52228800).

31125240 is an abundant number, since it is smaller than the sum of its proper divisors (73332360).

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

31125240 is a wasteful number, since it uses less digits than its factorization.

31125240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2837 (or 2830 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 31125240 is about 5578.9999103782. Note that the first 4 decimals coincide. The cubic root of 31125240 is about 314.5605360827.

Adding to 31125240 its reverse (4252113), we get a palindrome (35377353).

The spelling of 31125240 in words is "thirty-one million, one hundred twenty-five thousand, two hundred forty".