309220 has 12 divisors (see below), whose sum is σ = 649404. Its totient is φ = 123680.

The previous prime is 309193. The next prime is 309223. The reversal of 309220 is 22903.

It can be written as a sum of positive squares in 2 ways, for example, as 86436 + 222784 = 294^2 + 472^2 .

It is a nialpdrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 309194 and 309203.

It is not an unprimeable number, because it can be changed into a prime (309223) by changing a digit.

309220 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7711 + ... + 7750.

It is an arithmetic number, because the mean of its divisors is an integer number (54117).

2³⁰⁹²²⁰ is an apocalyptic number.

It is an amenable number.

309220 is an abundant number, since it is smaller than the sum of its proper divisors (340184).

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

309220 is a wasteful number, since it uses less digits than its factorization.

309220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15470 (or 15468 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 16.

The square root of 309220 is about 556.0755344375. The cubic root of 309220 is about 67.6221838190.

It can be divided in two parts, 309 and 220, that added together give a square (529 = 23²).

The spelling of 309220 in words is "three hundred nine thousand, two hundred twenty".