2001020221 has 4 divisors (see below), whose sum is σ = 2001671100. Its totient is φ = 2000369344.

The previous prime is 2001020183. The next prime is 2001020227. The reversal of 2001020221 is 1220201002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 805935321 + 1195084900 = 28389^2 + 34570^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2001020221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2001020198 and 2001020207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001020227) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 320806 + ... + 326983.

It is an arithmetic number, because the mean of its divisors is an integer number (500417775).

Almost surely, 2^2001020221 is an apocalyptic number.

It is an amenable number.

2001020221 is a deficient number, since it is larger than the sum of its proper divisors (650879).

2001020221 is an equidigital number, since it uses as much as digits as its factorization.

2001020221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 650878.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 2001020221 is about 44732.7645132737. The cubic root of 2001020221 is about 1260.1352464633.

Adding to 2001020221 its reverse (1220201002), we get a palindrome (3221221223).

The spelling of 2001020221 in words is "two billion, one million, twenty thousand, two hundred twenty-one".