31131120 has 80 divisors (see below), whose sum is σ = 101600640. Its totient is φ = 7863552.

The previous prime is 31131119. The next prime is 31131127. The reversal of 31131120 is 2113113.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 31131096 and 31131105.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31131127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1147 + ... + 7973.

It is an arithmetic number, because the mean of its divisors is an integer number (1270008).

Almost surely, 2^31131120 is an apocalyptic number.

31131120 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 31131120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50800320).

31131120 is an abundant number, since it is smaller than the sum of its proper divisors (70469520).

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

31131120 is a wasteful number, since it uses less digits than its factorization.

31131120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6862 (or 6856 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 31131120 is about 5579.5268616613. The cubic root of 31131120 is about 314.5803431534.

Adding to 31131120 its reverse (2113113), we get a palindrome (33244233).

The spelling of 31131120 in words is "thirty-one million, one hundred thirty-one thousand, one hundred twenty".