321649 has 4 divisors (see below), whose sum is σ = 323136. Its totient is φ = 320164.

The previous prime is 321647. The next prime is 321661. The reversal of 321649 is 946123.

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 321649 - 2¹ = 321647 is a prime.

It is a Duffinian number.

321649 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (321647) 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, 349 + ... + 874.

It is an arithmetic number, because the mean of its divisors is an integer number (80784).

2³²¹⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

321649 is a deficient number, since it is larger than the sum of its proper divisors (1487).

321649 is a wasteful number, since it uses less digits than its factorization.

321649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1486.

The product of its digits is 1296, while the sum is 25.

The square root of 321649 is about 567.1410759238. The cubic root of 321649 is about 68.5163262273.

It can be divided in two parts, 32 and 1649, that added together give a square (1681 = 41²).

The spelling of 321649 in words is "three hundred twenty-one thousand, six hundred forty-nine".