216720136517 has 8 divisors (see below), whose sum is σ = 217708012536. Its totient is φ = 215733949632.

The previous prime is 216720136499. The next prime is 216720136541. The reversal of 216720136517 is 715631027612.

216720136517 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 144581697121 + 72138439396 = 380239^2 + 268586^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 216720136517 - 2²² = 216715942213 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 (216720136597) by changing a digit.

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, 164738 + ... + 678659.

It is an arithmetic number, because the mean of its divisors is an integer number (27213501567).

Almost surely, 2^216720136517 is an apocalyptic number.

It is an amenable number.

216720136517 is a deficient number, since it is larger than the sum of its proper divisors (987876019).

216720136517 is an equidigital number, since it uses as much as digits as its factorization.

216720136517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 844567.

The product of its (nonzero) digits is 105840, while the sum is 41.

The spelling of 216720136517 in words is "two hundred sixteen billion, seven hundred twenty million, one hundred thirty-six thousand, five hundred seventeen".