8181815 has 4 divisors (see below), whose sum is σ = 9818184. Its totient is φ = 6545448.

The previous prime is 8181809. The next prime is 8181821. The reversal of 8181815 is 5181818.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5181818 = 2 ⋅2590909.

It is an interprime number because it is at equal distance from previous prime (8181809) and next prime (8181821).

It is a cyclic number.

It is not a de Polignac number, because 8181815 - 2⁶ = 8181751 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 818177 + ... + 818186.

It is an arithmetic number, because the mean of its divisors is an integer number (2454546).

Almost surely, 2^8181815 is an apocalyptic number.

8181815 is a deficient number, since it is larger than the sum of its proper divisors (1636369).

8181815 is a wasteful number, since it uses less digits than its factorization.

8181815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1636368.

The product of its digits is 2560, while the sum is 32.

The square root of 8181815 is about 2860.3872115502. The cubic root of 8181815 is about 201.5037897433.

The spelling of 8181815 in words is "eight million, one hundred eighty-one thousand, eight hundred fifteen".