2581665 has 16 divisors (see below), whose sum is σ = 4171200. Its totient is φ = 1363392.

The previous prime is 2581651. The next prime is 2581669. The reversal of 2581665 is 5661852.

It is not a de Polignac number, because 2581665 - 2⁵ = 2581633 is a prime.

2581665 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2581669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 846 + ... + 2424.

It is an arithmetic number, because the mean of its divisors is an integer number (260700).

2^2581665 is an apocalyptic number.

It is an amenable number.

2581665 is a deficient number, since it is larger than the sum of its proper divisors (1589535).

2581665 is a wasteful number, since it uses less digits than its factorization.

2581665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1696.

The product of its digits is 14400, while the sum is 33.

The square root of 2581665 is about 1606.7560486894. The cubic root of 2581665 is about 137.1828945913.

The spelling of 2581665 in words is "two million, five hundred eighty-one thousand, six hundred sixty-five".