2001645 has 16 divisors (see below), whose sum is σ = 3558720. Its totient is φ = 1067472.

The previous prime is 2001641. The next prime is 2001653. The reversal of 2001645 is 5461002.

It is a happy number.

2001645 is a `hidden beast` number, since 20 + 0 + 1 + 645 = 666.

It is not a de Polignac number, because 2001645 - 2² = 2001641 is a prime.

It is a super-3 number, since 3×2001645³ = 24059268721804233375, which contains 333 as substring.

It is a Curzon number.

2001645 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7279 + ... + 7548.

It is an arithmetic number, because the mean of its divisors is an integer number (222420).

2^2001645 is an apocalyptic number.

It is an amenable number.

2001645 is a deficient number, since it is larger than the sum of its proper divisors (1557075).

2001645 is a wasteful number, since it uses less digits than its factorization.

2001645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14841 (or 14835 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 2001645 is about 1414.7950381592. The cubic root of 2001645 is about 126.0266383588.

Adding to 2001645 its reverse (5461002), we get a palindrome (7462647).

The spelling of 2001645 in words is "two million, one thousand, six hundred forty-five".