31028220 has 72 divisors (see below), whose sum is σ = 94663296. Its totient is φ = 8226432.

The previous prime is 31028203. The next prime is 31028243. The reversal of 31028220 is 2282013.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 31028193 and 31028202.

It is a congruent number.

It is an unprimeable number.

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, 39754 + ... + 40526.

It is an arithmetic number, because the mean of its divisors is an integer number (1314768).

Almost surely, 2^31028220 is an apocalyptic number.

31028220 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 31028220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47331648).

31028220 is an abundant number, since it is smaller than the sum of its proper divisors (63635076).

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

31028220 is a wasteful number, since it uses less digits than its factorization.

31028220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1011 (or 1006 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 31028220 is about 5570.2980171621. The cubic root of 31028220 is about 314.2333586538.

The spelling of 31028220 in words is "thirty-one million, twenty-eight thousand, two hundred twenty".