321212220 has 96 divisors (see below), whose sum is σ = 1030288896. Its totient is φ = 73248000.

The previous prime is 321212197. The next prime is 321212231. The reversal of 321212220 is 22212123.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 321212220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 293875 + ... + 294965.

It is an arithmetic number, because the mean of its divisors is an integer number (10732176).

Almost surely, 2^321212220 is an apocalyptic number.

321212220 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 321212220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (515144448).

321212220 is an abundant number, since it is smaller than the sum of its proper divisors (709076676).

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

321212220 is a wasteful number, since it uses less digits than its factorization.

321212220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1811 (or 1809 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 321212220 is about 17922.3943712887. The cubic root of 321212220 is about 684.8529849486.

Adding to 321212220 its reverse (22212123), we get a palindrome (343424343).

The spelling of 321212220 in words is "three hundred twenty-one million, two hundred twelve thousand, two hundred twenty".