20021231220 has 24 divisors (see below), whose sum is σ = 56059447584. Its totient is φ = 5338994976.

The previous prime is 20021231203. The next prime is 20021231231. The reversal of 20021231220 is 2213212002.

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 20021231220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 166843534 + ... + 166843653.

It is an arithmetic number, because the mean of its divisors is an integer number (2335810316).

Almost surely, 2^20021231220 is an apocalyptic number.

20021231220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20021231220 is an abundant number, since it is smaller than the sum of its proper divisors (36038216364).

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

20021231220 is a wasteful number, since it uses less digits than its factorization.

20021231220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333687199 (or 333687197 counting only the distinct ones).

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

Adding to 20021231220 its reverse (2213212002), we get a palindrome (22234443222).

The spelling of 20021231220 in words is "twenty billion, twenty-one million, two hundred thirty-one thousand, two hundred twenty".