2001443581 has 2 divisors, whose sum is σ = 2001443582. Its totient is φ = 2001443580.

The previous prime is 2001443569. The next prime is 2001443623. The reversal of 2001443581 is 1853441002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1965503556 + 35940025 = 44334^2 + 5995^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001443581 - 2¹⁵ = 2001410813 is a prime.

It is a super-2 number, since 2×2001443581² = 8011552815852207122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001443551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000721790 + 1000721791.

It is an arithmetic number, because the mean of its divisors is an integer number (1000721791).

Almost surely, 2^2001443581 is an apocalyptic number.

It is an amenable number.

2001443581 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001443581 is an equidigital number, since it uses as much as digits as its factorization.

2001443581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 2001443581 is about 44737.4963649063. The cubic root of 2001443581 is about 1260.2241100061.

Adding to 2001443581 its reverse (1853441002), we get a palindrome (3854884583).

The spelling of 2001443581 in words is "two billion, one million, four hundred forty-three thousand, five hundred eighty-one".