2001321 has 16 divisors (see below), whose sum is σ = 3388800. Its totient is φ = 1143504.

The previous prime is 2001313. The next prime is 2001331. The reversal of 2001321 is 1231002.

It is a happy number.

It is not a de Polignac number, because 2001321 - 2³ = 2001313 is a prime.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2001331) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 5106 + ... + 5483.

It is an arithmetic number, because the mean of its divisors is an integer number (211800).

2^2001321 is an apocalyptic number.

2001321 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2001321 is a deficient number, since it is larger than the sum of its proper divisors (1387479).

2001321 is a wasteful number, since it uses less digits than its factorization.

2001321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10605 (or 10599 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 2001321 is about 1414.6805293069. The cubic root of 2001321 is about 126.0198381462.

Adding to 2001321 its reverse (1231002), we get a palindrome (3232323).

It can be divided in two parts, 200 and 1321, that added together give a square (1521 = 39²).

The spelling of 2001321 in words is "two million, one thousand, three hundred twenty-one".