2640635 has 4 divisors (see below), whose sum is σ = 3168768. Its totient is φ = 2112504.

The previous prime is 2640581. The next prime is 2640643. The reversal of 2640635 is 5360462.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5360462 = 2 ⋅2680231.

It is a cyclic number.

It is not a de Polignac number, because 2640635 - 2⁶ = 2640571 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 264059 + ... + 264068.

It is an arithmetic number, because the mean of its divisors is an integer number (792192).

2^2640635 is an apocalyptic number.

2640635 is a deficient number, since it is larger than the sum of its proper divisors (528133).

2640635 is an equidigital number, since it uses as much as digits as its factorization.

2640635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528132.

The product of its (nonzero) digits is 4320, while the sum is 26.

The square root of 2640635 is about 1625.0030769202. The cubic root of 2640635 is about 138.2195448199.

The spelling of 2640635 in words is "two million, six hundred forty thousand, six hundred thirty-five".