216851864307565 has 8 divisors (see below), whose sum is σ = 260252776151928. Its totient is φ = 173461132124160.

The previous prime is 216851864307563. The next prime is 216851864307569. The reversal of 216851864307565 is 565703468158612.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 76564635014884 + 140287229292681 = 8750122^2 + 11844291^2 .

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

It is not a de Polignac number, because 216851864307565 - 2¹ = 216851864307563 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 216851864307565.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216851864307563) 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, 2544868372 + ... + 2544953581.

It is an arithmetic number, because the mean of its divisors is an integer number (32531597018991).

Almost surely, 2^{216851864307565} is an apocalyptic number.

It is an amenable number.

216851864307565 is a deficient number, since it is larger than the sum of its proper divisors (43400911844363).

216851864307565 is an equidigital number, since it uses as much as digits as its factorization.

216851864307565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5089830479.

The product of its (nonzero) digits is 290304000, while the sum is 67.

The spelling of 216851864307565 in words is "two hundred sixteen trillion, eight hundred fifty-one billion, eight hundred sixty-four million, three hundred seven thousand, five hundred sixty-five".