2640321 has 12 divisors (see below), whose sum is σ = 4038372. Its totient is φ = 1656576.

The previous prime is 2640317. The next prime is 2640343. The reversal of 2640321 is 1230462.

It is a happy number.

2640321 is a `hidden beast` number, since 2 + 640 + 3 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 921600 + 1718721 = 960^2 + 1311^2 .

It is not a de Polignac number, because 2640321 - 2² = 2640317 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2640294 and 2640303.

It is not an unprimeable number, because it can be changed into a prime (2640361) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8476 + ... + 8781.

It is an arithmetic number, because the mean of its divisors is an integer number (336531).

2^2640321 is an apocalyptic number.

It is an amenable number.

2640321 is a deficient number, since it is larger than the sum of its proper divisors (1398051).

2640321 is a wasteful number, since it uses less digits than its factorization.

2640321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17280 (or 17277 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 2640321 is about 1624.9064588462. The cubic root of 2640321 is about 138.2140660042.

Adding to 2640321 its reverse (1230462), we get a palindrome (3870783).

The spelling of 2640321 in words is "two million, six hundred forty thousand, three hundred twenty-one".