2001816 has 24 divisors (see below), whose sum is σ = 5421780. Its totient is φ = 667248.

The previous prime is 2001809. The next prime is 2001833. The reversal of 2001816 is 6181002.

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13830 + ... + 13973.

2^2001816 is an apocalyptic number.

It is an amenable number.

2001816 is an abundant number, since it is smaller than the sum of its proper divisors (3419964).

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

2001816 is a wasteful number, since it uses less digits than its factorization.

2001816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27815 (or 27808 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 2001816 is about 1414.8554696505. The cubic root of 2001816 is about 126.0302270640.

Adding to 2001816 its reverse (6181002), we get a palindrome (8182818).

It can be divided in two parts, 200 and 1816, that added together give a triangular number (2016 = T₆₃).

The spelling of 2001816 in words is "two million, one thousand, eight hundred sixteen".