3809721 has 4 divisors (see below), whose sum is σ = 5079632. Its totient is φ = 2539812.

The previous prime is 3809719. The next prime is 3809723. The reversal of 3809721 is 1279083.

It is a happy number.

3809721 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 Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (3809719) and next prime (3809723).

It is not a de Polignac number, because 3809721 - 2¹ = 3809719 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3809723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 634951 + ... + 634956.

It is an arithmetic number, because the mean of its divisors is an integer number (1269908).

Almost surely, 2^3809721 is an apocalyptic number.

It is an amenable number.

3809721 is a deficient number, since it is larger than the sum of its proper divisors (1269911).

3809721 is a wasteful number, since it uses less digits than its factorization.

3809721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1269910.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 3809721 is about 1951.8506602709. The cubic root of 3809721 is about 156.1820278216.

It can be divided in two parts, 380 and 9721, that added together give a palindrome (10101).

The spelling of 3809721 in words is "three million, eight hundred nine thousand, seven hundred twenty-one".