3591721 has 4 divisors (see below), whose sum is σ = 4104832. Its totient is φ = 3078612.

The previous prime is 3591719. The next prime is 3591733. The reversal of 3591721 is 1271953.

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 not a de Polignac number, because 3591721 - 2¹ = 3591719 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 3591721.

It is not an unprimeable number, because it can be changed into a prime (3591761) 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, 256545 + ... + 256558.

It is an arithmetic number, because the mean of its divisors is an integer number (1026208).

Almost surely, 2^3591721 is an apocalyptic number.

It is an amenable number.

3591721 is a deficient number, since it is larger than the sum of its proper divisors (513111).

3591721 is an equidigital number, since it uses as much as digits as its factorization.

3591721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 513110.

The product of its digits is 1890, while the sum is 28.

The square root of 3591721 is about 1895.1836322636. The cubic root of 3591721 is about 153.1443097126.

It can be divided in two parts, 359 and 1721, that added together give a triangular number (2080 = T₆₄).

The spelling of 3591721 in words is "three million, five hundred ninety-one thousand, seven hundred twenty-one".