3201721 has 4 divisors (see below), whose sum is σ = 3288292. Its totient is φ = 3115152.

The previous prime is 3201719. The next prime is 3201727. The reversal of 3201721 is 1271023.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1271023 = 13 ⋅97771.

It can be written as a sum of positive squares in 2 ways, for example, as 1297321 + 1904400 = 1139^2 + 1380^2 .

It is a cyclic number.

It is not a de Polignac number, because 3201721 - 2¹ = 3201719 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3201695 and 3201704.

It is not an unprimeable number, because it can be changed into a prime (3201727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43230 + ... + 43303.

It is an arithmetic number, because the mean of its divisors is an integer number (822073).

Almost surely, 2^3201721 is an apocalyptic number.

It is an amenable number.

3201721 is a deficient number, since it is larger than the sum of its proper divisors (86571).

3201721 is an equidigital number, since it uses as much as digits as its factorization.

3201721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86570.

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 3201721 is about 1789.3353514643. The cubic root of 3201721 is about 147.3876727870.

Adding to 3201721 its reverse (1271023), we get a palindrome (4472744).

The spelling of 3201721 in words is "three million, two hundred one thousand, seven hundred twenty-one".