7881665 has 16 divisors (see below), whose sum is σ = 10540800. Its totient is φ = 5608320.

The previous prime is 7881647. The next prime is 7881689. The reversal of 7881665 is 5661887.

It is not a de Polignac number, because 7881665 - 2¹⁰ = 7880641 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1061 + ... + 4109.

It is an arithmetic number, because the mean of its divisors is an integer number (658800).

Almost surely, 2^7881665 is an apocalyptic number.

It is an amenable number.

7881665 is a deficient number, since it is larger than the sum of its proper divisors (2659135).

7881665 is a wasteful number, since it uses less digits than its factorization.

7881665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3112.

The product of its digits is 80640, while the sum is 41.

The square root of 7881665 is about 2807.4303197052. The cubic root of 7881665 is about 199.0089724328.

The spelling of 7881665 in words is "seven million, eight hundred eighty-one thousand, six hundred sixty-five".