2640865 has 8 divisors (see below), whose sum is σ = 3355560. Its totient is φ = 1988352.

The previous prime is 2640863. The next prime is 2640871. The reversal of 2640865 is 5680462.

It can be written as a sum of positive squares in 4 ways, for example, as 613089 + 2027776 = 783^2 + 1424^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2640865 - 2¹ = 2640863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2640863) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15450 + ... + 15619.

It is an arithmetic number, because the mean of its divisors is an integer number (419445).

2^2640865 is an apocalyptic number.

It is an amenable number.

2640865 is a deficient number, since it is larger than the sum of its proper divisors (714695).

2640865 is a wasteful number, since it uses less digits than its factorization.

2640865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31091.

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 2640865 is about 1625.0738444760. The cubic root of 2640865 is about 138.2235576895.

The spelling of 2640865 in words is "two million, six hundred forty thousand, eight hundred sixty-five".