20321220 has 24 divisors (see below), whose sum is σ = 56899584. Its totient is φ = 5418976.

The previous prime is 20321201. The next prime is 20321233. The reversal of 20321220 is 2212302.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 20321196 and 20321205.

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, 169284 + ... + 169403.

It is an arithmetic number, because the mean of its divisors is an integer number (2370816).

Almost surely, 2^20321220 is an apocalyptic number.

20321220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20321220 is an abundant number, since it is smaller than the sum of its proper divisors (36578364).

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

20321220 is a wasteful number, since it uses less digits than its factorization.

20321220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338699 (or 338697 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 20321220 is about 4507.9063876704. The cubic root of 20321220 is about 272.8872590603.

Adding to 20321220 its reverse (2212302), we get a palindrome (22533522).

The spelling of 20321220 in words is "twenty million, three hundred twenty-one thousand, two hundred twenty".