999808665 has 8 divisors (see below), whose sum is σ = 1599693888. Its totient is φ = 533231280.

The previous prime is 999808661. The next prime is 999808673. The reversal of 999808665 is 566808999.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 999808665 - 2² = 999808661 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 999808599 and 999808608.

It is not an unprimeable number, because it can be changed into a prime (999808661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33326941 + ... + 33326970.

It is an arithmetic number, because the mean of its divisors is an integer number (199961736).

Almost surely, 2^999808665 is an apocalyptic number.

It is an amenable number.

999808665 is a deficient number, since it is larger than the sum of its proper divisors (599885223).

999808665 is a wasteful number, since it uses less digits than its factorization.

999808665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66653919.

The product of its (nonzero) digits is 8398080, while the sum is 60.

The square root of 999808665 is about 31619.7511849793. The cubic root of 999808665 is about 999.9362175986.

The spelling of 999808665 in words is "nine hundred ninety-nine million, eight hundred eight thousand, six hundred sixty-five".