816585881 has 4 divisors (see below), whose sum is σ = 816643200. Its totient is φ = 816528564.

The previous prime is 816585877. The next prime is 816585919. The reversal of 816585881 is 188585618.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 816585881 - 2² = 816585877 is a prime.

It is a super-2 number, since 2×816585881² = 1333625002097092322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (816585841) 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, 11060 + ... + 41898.

It is an arithmetic number, because the mean of its divisors is an integer number (204160800).

Almost surely, 2^816585881 is an apocalyptic number.

It is an amenable number.

816585881 is a deficient number, since it is larger than the sum of its proper divisors (57319).

816585881 is a wasteful number, since it uses less digits than its factorization.

816585881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57318.

The product of its digits is 614400, while the sum is 50.

The square root of 816585881 is about 28575.9668427859. The cubic root of 816585881 is about 934.6893382968.

The spelling of 816585881 in words is "eight hundred sixteen million, five hundred eighty-five thousand, eight hundred eighty-one".