3721 has 3 divisors (see below), whose sum is σ = 3783. Its totient is φ = 3660.

The previous prime is 3719. The next prime is 3727. The reversal of 3721 is 1273.

3721 = T₆₀ + T₆₁.

The square root of 3721 is 61.

It is a perfect power (a square), and thus also a powerful number.

3721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1273 = 19 ⋅67.

It can be written as a sum of positive squares in only one way, i.e., 121 + 3600 = 11^2 + 60^2 .

It is not a de Polignac number, because 3721 - 2¹ = 3719 is a prime.

It is a Duffinian number.

3721 is a lucky number.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (3727) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 31 + ... + 91.

It is an arithmetic number, because the mean of its divisors is an integer number (1261).

2³⁷²¹ is an apocalyptic number.

3721 is the 61-st square number.

3721 is the 31-st centered octagonal number.

It is an amenable number.

3721 is a deficient number, since it is larger than the sum of its proper divisors (62).

3721 is an frugal number, since it uses more digits than its factorization.

3721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122 (or 61 counting only the distinct ones).

The product of its digits is 42, while the sum is 13.

The cubic root of 3721 is about 15.4960100726.

Adding to 3721 its reverse (1273), we get a palindrome (4994).

It can be divided in two parts, 372 and 1, that added together give a palindrome (373).

The spelling of 3721 in words is "three thousand, seven hundred twenty-one", and thus it is an iban number.