815936881 has 4 divisors (see below), whose sum is σ = 816102000. Its totient is φ = 815771764.

The previous prime is 815936867. The next prime is 815936887. The reversal of 815936881 is 188639518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 815936881 - 2¹⁵ = 815904113 is a prime.

It is a super-2 number, since 2×815936881² = 1331505987552016322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (815936887) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 74911 + ... + 85108.

It is an arithmetic number, because the mean of its divisors is an integer number (204025500).

Almost surely, 2^815936881 is an apocalyptic number.

It is an amenable number.

815936881 is a deficient number, since it is larger than the sum of its proper divisors (165119).

815936881 is a wasteful number, since it uses less digits than its factorization.

815936881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165118.

The product of its digits is 414720, while the sum is 49.

The square root of 815936881 is about 28564.6088893232. The cubic root of 815936881 is about 934.4416508736.

The spelling of 815936881 in words is "eight hundred fifteen million, nine hundred thirty-six thousand, eight hundred eighty-one".