2001721683 has 18 divisors (see below), whose sum is σ = 2891514924. Its totient is φ = 1231208784.

The previous prime is 2001721679. The next prime is 2001721691. The reversal of 2001721683 is 3861271002.

It is not a de Polignac number, because 2001721683 - 2² = 2001721679 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2001721683.

It is not an unprimeable number, because it can be changed into a prime (2001721693) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1006416 + ... + 1008402.

It is an arithmetic number, because the mean of its divisors is an integer number (160639718).

Almost surely, 2^2001721683 is an apocalyptic number.

2001721683 is a deficient number, since it is larger than the sum of its proper divisors (889793241).

2001721683 is an frugal number, since it uses more digits than its factorization.

2001721683 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4003 (or 2003 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 2001721683 is about 44740.6044103117. The cubic root of 2001721683 is about 1260.2824769797.

Adding to 2001721683 its reverse (3861271002), we get a palindrome (5862992685).

The spelling of 2001721683 in words is "two billion, one million, seven hundred twenty-one thousand, six hundred eighty-three".