163817865 has 24 divisors (see below), whose sum is σ = 300655368. Its totient is φ = 82229760.

The previous prime is 163817813. The next prime is 163817869. The reversal of 163817865 is 568718361.

163817865 is a `hidden beast` number, since 1 + 638 + 1 + 7 + 8 + 6 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 35426304 + 128391561 = 5952^2 + 11331^2 .

It is not a de Polignac number, because 163817865 - 2⁷ = 163817737 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 163817865.

It is not an unprimeable number, because it can be changed into a prime (163817869) 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 23 ways as a sum of consecutive naturals, for example, 106306 + ... + 107835.

It is an arithmetic number, because the mean of its divisors is an integer number (12527307).

Almost surely, 2^163817865 is an apocalyptic number.

163817865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

163817865 is a deficient number, since it is larger than the sum of its proper divisors (136837503).

163817865 is a wasteful number, since it uses less digits than its factorization.

163817865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214169 (or 214166 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The square root of 163817865 is about 12799.1353223567. The cubic root of 163817865 is about 547.1676596929.

It can be divided in two parts, 1638 and 17865, that added together give a triangular number (19503 = T₁₉₇).

The spelling of 163817865 in words is "one hundred sixty-three million, eight hundred seventeen thousand, eight hundred sixty-five".