311221220 has 24 divisors (see below), whose sum is σ = 654247608. Its totient is φ = 124358400.

The previous prime is 311221213. The next prime is 311221223. The reversal of 311221220 is 22122113.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 76457536 + 234763684 = 8744^2 + 15322^2 .

It is a super-3 number, since 3×311221220³ (a number of 26 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 311221195 and 311221204.

It is not an unprimeable number, because it can be changed into a prime (311221223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12800 + ... + 28040.

It is an arithmetic number, because the mean of its divisors is an integer number (27260317).

Almost surely, 2^311221220 is an apocalyptic number.

It is an amenable number.

311221220 is an abundant number, since it is smaller than the sum of its proper divisors (343026388).

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

311221220 is a wasteful number, since it uses less digits than its factorization.

311221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16271 (or 16269 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 311221220 is about 17641.4630912518. The cubic root of 311221220 is about 677.6775005479.

Adding to 311221220 its reverse (22122113), we get a palindrome (333343333).

The spelling of 311221220 in words is "three hundred eleven million, two hundred twenty-one thousand, two hundred twenty".