3131220 has 48 divisors (see below), whose sum is σ = 9152640. Its totient is φ = 798336.

The previous prime is 3131209. The next prime is 3131221. The reversal of 3131220 is 221313.

It is a happy number.

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 = 3131196 and 3131205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3131221) 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, 246 + ... + 2514.

It is an arithmetic number, because the mean of its divisors is an integer number (190680).

Almost surely, 2^3131220 is an apocalyptic number.

3131220 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 3131220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4576320).

3131220 is an abundant number, since it is smaller than the sum of its proper divisors (6021420).

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

3131220 is a wasteful number, since it uses less digits than its factorization.

3131220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2304 (or 2302 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 3131220 is about 1769.5253600895. The cubic root of 3131220 is about 146.2978220409.

Adding to 3131220 its reverse (221313), we get a palindrome (3352533).

The spelling of 3131220 in words is "three million, one hundred thirty-one thousand, two hundred twenty".