2800865 has 4 divisors (see below), whose sum is σ = 3361044. Its totient is φ = 2240688.

The previous prime is 2800859. The next prime is 2800873. The reversal of 2800865 is 5680082.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5680082 = 2 ⋅2840041.

It can be written as a sum of positive squares in 2 ways, for example, as 1079521 + 1721344 = 1039^2 + 1312^2 .

It is a cyclic number.

It is not a de Polignac number, because 2800865 - 2¹⁶ = 2735329 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, 280082 + ... + 280091.

It is an arithmetic number, because the mean of its divisors is an integer number (840261).

2^2800865 is an apocalyptic number.

It is an amenable number.

2800865 is a deficient number, since it is larger than the sum of its proper divisors (560179).

2800865 is an equidigital number, since it uses as much as digits as its factorization.

2800865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560178.

The product of its (nonzero) digits is 3840, while the sum is 29.

The square root of 2800865 is about 1673.5785012960. The cubic root of 2800865 is about 140.9604872265.

The spelling of 2800865 in words is "two million, eight hundred thousand, eight hundred sixty-five".