221020020 has 144 divisors (see below), whose sum is σ = 747124560. Its totient is φ = 52512768.

The previous prime is 221020003. The next prime is 221020039. The reversal of 221020020 is 20020122.

It can be written as a sum of positive squares in 8 ways, for example, as 675684 + 220344336 = 822^2 + 14844^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 221019984 and 221020011.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 66232 + ... + 69488.

It is an arithmetic number, because the mean of its divisors is an integer number (5188365).

Almost surely, 2^221020020 is an apocalyptic number.

221020020 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 221020020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (373562280).

221020020 is an abundant number, since it is smaller than the sum of its proper divisors (526104540).

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

221020020 is a wasteful number, since it uses less digits than its factorization.

221020020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3314 (or 3309 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 221020020 is about 14866.7420775367. The cubic root of 221020020 is about 604.6126154287.

Adding to 221020020 its reverse (20020122), we get a palindrome (241040142).

The spelling of 221020020 in words is "two hundred twenty-one million, twenty thousand, twenty".