2001021111 has 16 divisors (see below), whose sum is σ = 2973445120. Its totient is φ = 1329977880.

The previous prime is 2001021109. The next prime is 2001021149. The reversal of 2001021111 is 1111201002.

It is a happy number.

It is not a de Polignac number, because 2001021111 - 2¹ = 2001021109 is a prime.

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

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2001021093 and 2001021102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001021101) 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 15 ways as a sum of consecutive naturals, for example, 103015 + ... + 120888.

It is an arithmetic number, because the mean of its divisors is an integer number (185840320).

Almost surely, 2^2001021111 is an apocalyptic number.

2001021111 is a deficient number, since it is larger than the sum of its proper divisors (972424009).

2001021111 is a wasteful number, since it uses less digits than its factorization.

2001021111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224243 (or 224237 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 2001021111 is about 44732.7744612381. The cubic root of 2001021111 is about 1260.1354332880.

Adding to 2001021111 its reverse (1111201002), we get a palindrome (3112222113).

The spelling of 2001021111 in words is "two billion, one million, twenty-one thousand, one hundred eleven".