20021021220 has 24 divisors (see below), whose sum is σ = 56058859584. Its totient is φ = 5338938976.

The previous prime is 20021021203. The next prime is 20021021249. The reversal of 20021021220 is 2212012002.

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 = 20021021196 and 20021021205.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 166841784 + ... + 166841903.

It is an arithmetic number, because the mean of its divisors is an integer number (2335785816).

Almost surely, 2^20021021220 is an apocalyptic number.

20021021220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20021021220 is an abundant number, since it is smaller than the sum of its proper divisors (36037838364).

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

20021021220 is a wasteful number, since it uses less digits than its factorization.

20021021220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333683699 (or 333683697 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 20021021220 its reverse (2212012002), we get a palindrome (22233033222).

The spelling of 20021021220 in words is "twenty billion, twenty-one million, twenty-one thousand, two hundred twenty".