321131220 has 24 divisors (see below), whose sum is σ = 899167584. Its totient is φ = 85634976.

The previous prime is 321131219. The next prime is 321131231. The reversal of 321131220 is 22131123.

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 321131220.

It is a congruent number.

It is an unprimeable 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 7 ways as a sum of consecutive naturals, for example, 2676034 + ... + 2676153.

It is an arithmetic number, because the mean of its divisors is an integer number (37465316).

Almost surely, 2^321131220 is an apocalyptic number.

321131220 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

321131220 is an abundant number, since it is smaller than the sum of its proper divisors (578036364).

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

321131220 is a wasteful number, since it uses less digits than its factorization.

321131220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5352199 (or 5352197 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 321131220 is about 17920.1344861025. The cubic root of 321131220 is about 684.7954137108.

Adding to 321131220 its reverse (22131123), we get a palindrome (343262343).

It can be divided in two parts, 32113 and 1220, that added together give a palindrome (33333).

The spelling of 321131220 in words is "three hundred twenty-one million, one hundred thirty-one thousand, two hundred twenty".