201221220020 has 24 divisors (see below), whose sum is σ = 422997115464. Its totient is φ = 80406096896.

The previous prime is 201221219989. The next prime is 201221220047. The reversal of 201221220020 is 20022122102.

It can be written as a sum of positive squares in 4 ways, for example, as 53583916324 + 147637303696 = 231482^2 + 384236^2 .

It is a junction number, because it is equal to n+sod(n) for n = 201221219977 and 201221220004.

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, 5129417 + ... + 5168496.

It is an arithmetic number, because the mean of its divisors is an integer number (17624879811).

Almost surely, 2^201221220020 is an apocalyptic number.

201221220020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

201221220020 is an abundant number, since it is smaller than the sum of its proper divisors (221775895444).

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

201221220020 is a wasteful number, since it uses less digits than its factorization.

201221220020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10298899 (or 10298897 counting only the distinct ones).

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

Adding to 201221220020 its reverse (20022122102), we get a palindrome (221243342122).

The spelling of 201221220020 in words is "two hundred one billion, two hundred twenty-one million, two hundred twenty thousand, twenty".