2001321021 has 32 divisors (see below), whose sum is σ = 3100887040. Its totient is φ = 1124456256.

The previous prime is 2001321019. The next prime is 2001321029. The reversal of 2001321021 is 1201231002.

It is not a de Polignac number, because 2001321021 - 2¹ = 2001321019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2001320988 and 2001321006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001321029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1064160 + ... + 1066038.

It is an arithmetic number, because the mean of its divisors is an integer number (96902720).

Almost surely, 2^2001321021 is an apocalyptic number.

2001321021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2001321021 is a deficient number, since it is larger than the sum of its proper divisors (1099566019).

2001321021 is a wasteful number, since it uses less digits than its factorization.

2001321021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2713.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 2001321021 is about 44736.1265757330. The cubic root of 2001321021 is about 1260.1983858703.

Adding to 2001321021 its reverse (1201231002), we get a palindrome (3202552023).

The spelling of 2001321021 in words is "two billion, one million, three hundred twenty-one thousand, twenty-one".