2640404 has 12 divisors (see below), whose sum is σ = 4976244. Its totient is φ = 1218624.

The previous prime is 2640397. The next prime is 2640409. The reversal of 2640404 is 4040462.

It can be written as a sum of positive squares in 2 ways, for example, as 1322500 + 1317904 = 1150^2 + 1148^2 .

2640404 is a modest number, since divided by 404 gives 264 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2640409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25337 + ... + 25440.

It is an arithmetic number, because the mean of its divisors is an integer number (414687).

2^2640404 is an apocalyptic number.

It is an amenable number.

2640404 is a deficient number, since it is larger than the sum of its proper divisors (2335840).

2640404 is a wasteful number, since it uses less digits than its factorization.

2640404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50794 (or 50792 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 2640404 is about 1624.9319985772. The cubic root of 2640404 is about 138.2155142684.

Adding to 2640404 its reverse (4040462), we get a palindrome (6680866).

The spelling of 2640404 in words is "two million, six hundred forty thousand, four hundred four".