3721661 has 4 divisors (see below), whose sum is σ = 3784800. Its totient is φ = 3658524.

The previous prime is 3721631. The next prime is 3721673. The reversal of 3721661 is 1661273.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3721661 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 3721661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3721621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31481 + ... + 31598.

It is an arithmetic number, because the mean of its divisors is an integer number (946200).

Almost surely, 2^3721661 is an apocalyptic number.

It is an amenable number.

3721661 is a deficient number, since it is larger than the sum of its proper divisors (63139).

3721661 is an equidigital number, since it uses as much as digits as its factorization.

3721661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63138.

The product of its digits is 1512, while the sum is 26.

The square root of 3721661 is about 1929.1606983349. The cubic root of 3721661 is about 154.9692759082.

The spelling of 3721661 in words is "three million, seven hundred twenty-one thousand, six hundred sixty-one".