865161999 has 16 divisors (see below), whose sum is σ = 1380316000. Its totient is φ = 532407168.

The previous prime is 865161991. The next prime is 865162007. The reversal of 865161999 is 999161568.

865161999 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (865161991) and next prime (865162007).

It is not a de Polignac number, because 865161999 - 2³ = 865161991 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 (865161991) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1232074 + ... + 1232775.

It is an arithmetic number, because the mean of its divisors is an integer number (86269750).

Almost surely, 2^865161999 is an apocalyptic number.

865161999 is a deficient number, since it is larger than the sum of its proper divisors (515154001).

865161999 is a wasteful number, since it uses less digits than its factorization.

865161999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2464871 (or 2464865 counting only the distinct ones).

The product of its digits is 1049760, while the sum is 54.

The square root of 865161999 is about 29413.6362763940. The cubic root of 865161999 is about 952.8674210265.

The spelling of 865161999 in words is "eight hundred sixty-five million, one hundred sixty-one thousand, nine hundred ninety-nine".