16538878765 has 8 divisors (see below), whose sum is σ = 19874970648. Its totient is φ = 13212225600.

The previous prime is 16538878693. The next prime is 16538878813. The reversal of 16538878765 is 56787883561.

It can be written as a sum of positive squares in 4 ways, for example, as 4063552516 + 12475326249 = 63746^2 + 111693^2 .

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

It is not a de Polignac number, because 16538878765 - 2²⁵ = 16505324333 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16538878697 and 16538878706.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2355822 + ... + 2362831.

It is an arithmetic number, because the mean of its divisors is an integer number (2484371331).

Almost surely, 2^16538878765 is an apocalyptic number.

It is an amenable number.

16538878765 is a deficient number, since it is larger than the sum of its proper divisors (3336091883).

16538878765 is an equidigital number, since it uses as much as digits as its factorization.

16538878765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4719359.

The product of its digits is 67737600, while the sum is 64.

The spelling of 16538878765 in words is "sixteen billion, five hundred thirty-eight million, eight hundred seventy-eight thousand, seven hundred sixty-five".