2001002021 has 4 divisors (see below), whose sum is σ = 2001096972. Its totient is φ = 2000907072.

The previous prime is 2001002011. The next prime is 2001002057. The reversal of 2001002021 is 1202001002.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1202001002 = 2 ⋅601000501.

It can be written as a sum of positive squares in 2 ways, for example, as 359860900 + 1641141121 = 18970^2 + 40511^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2001002021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001002011) 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, 116 + ... + 63261.

It is an arithmetic number, because the mean of its divisors is an integer number (500274243).

Almost surely, 2^2001002021 is an apocalyptic number.

It is an amenable number.

2001002021 is a deficient number, since it is larger than the sum of its proper divisors (94951).

2001002021 is an equidigital number, since it uses as much as digits as its factorization.

2001002021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94950.

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 2001002021 is about 44732.5610825045. The cubic root of 2001002021 is about 1260.1314259903.

Adding to 2001002021 its reverse (1202001002), we get a palindrome (3203003023).

The spelling of 2001002021 in words is "two billion, one million, two thousand, twenty-one".