7991815 has 16 divisors (see below), whose sum is σ = 10610208. Its totient is φ = 5740416.

The previous prime is 7991803. The next prime is 7991839. The reversal of 7991815 is 5181997.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 7991815 - 2⁹ = 7991303 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 744 + ... + 4066.

It is an arithmetic number, because the mean of its divisors is an integer number (663138).

Almost surely, 2^7991815 is an apocalyptic number.

7991815 is a deficient number, since it is larger than the sum of its proper divisors (2618393).

7991815 is a wasteful number, since it uses less digits than its factorization.

7991815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3378.

The product of its digits is 22680, while the sum is 40.

The square root of 7991815 is about 2826.9798372114. The cubic root of 7991815 is about 199.9317683916.

The spelling of 7991815 in words is "seven million, nine hundred ninety-one thousand, eight hundred fifteen".