2639865 has 8 divisors (see below), whose sum is σ = 4223808. Its totient is φ = 1407920.

The previous prime is 2639863. The next prime is 2639869. The reversal of 2639865 is 5689362.

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

It is not a de Polignac number, because 2639865 - 2¹ = 2639863 is a prime.

It is an Ulam number.

It is a d-powerful number, because it can be written as 2²¹ + 6⁴ + 3⁷ + 9⁶ + 8 + 6⁵ + 5 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2639863) 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, 87981 + ... + 88010.

It is an arithmetic number, because the mean of its divisors is an integer number (527976).

2^2639865 is an apocalyptic number.

It is an amenable number.

2639865 is a deficient number, since it is larger than the sum of its proper divisors (1583943).

2639865 is a wasteful number, since it uses less digits than its factorization.

2639865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175999.

The product of its digits is 77760, while the sum is 39.

The square root of 2639865 is about 1624.7661370179. The cubic root of 2639865 is about 138.2061087340.

The spelling of 2639865 in words is "two million, six hundred thirty-nine thousand, eight hundred sixty-five".