20021221220 has 192 divisors, whose sum is σ = 57170534400. Its totient is φ = 5686986240.

The previous prime is 20021221211. The next prime is 20021221277. The reversal of 20021221220 is 2212212002.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 20021221195 and 20021221204.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1575251 + ... + 1587909.

It is an arithmetic number, because the mean of its divisors is an integer number (297763200).

Almost surely, 2^20021221220 is an apocalyptic number.

20021221220 is a gapful number since it is divisible by the number (20) 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 20021221220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28585267200).

20021221220 is an abundant number, since it is smaller than the sum of its proper divisors (37149313180).

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

20021221220 is a wasteful number, since it uses less digits than its factorization.

20021221220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12778 (or 12776 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 20021221220 its reverse (2212212002), we get a palindrome (22233433222).

The spelling of 20021221220 in words is "twenty billion, twenty-one million, two hundred twenty-one thousand, two hundred twenty".