8815991 has 4 divisors (see below), whose sum is σ = 8936832. Its totient is φ = 8695152.

The previous prime is 8815973. The next prime is 8816053. The reversal of 8815991 is 1995188.

8815991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 8815991 - 2¹⁴ = 8799607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8815951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60311 + ... + 60456.

It is an arithmetic number, because the mean of its divisors is an integer number (2234208).

Almost surely, 2^8815991 is an apocalyptic number.

8815991 is a deficient number, since it is larger than the sum of its proper divisors (120841).

8815991 is a wasteful number, since it uses less digits than its factorization.

8815991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120840.

The product of its digits is 25920, while the sum is 41.

The square root of 8815991 is about 2969.1734540104. The cubic root of 8815991 is about 206.5810018994.

The spelling of 8815991 in words is "eight million, eight hundred fifteen thousand, nine hundred ninety-one".