16720120784138 has 16 divisors (see below), whose sum is σ = 26818411560264. Its totient is φ = 7790388249600.

The previous prime is 16720120784137. The next prime is 16720120784153. The reversal of 16720120784138 is 83148702102761.

16720120784138 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 15219650130169 + 1500470653969 = 3901237^2 + 1224937^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16720120784137) 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, 2434492895 + ... + 2434499762.

Almost surely, 2^{16720120784138} is an apocalyptic number.

16720120784138 is a deficient number, since it is larger than the sum of its proper divisors (10098290776126).

16720120784138 is a wasteful number, since it uses less digits than its factorization.

16720120784138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4868992777.

The product of its (nonzero) digits is 903168, while the sum is 50.

Adding to 16720120784138 its reverse (83148702102761), we get a palindrome (99868822886899).

The spelling of 16720120784138 in words is "sixteen trillion, seven hundred twenty billion, one hundred twenty million, seven hundred eighty-four thousand, one hundred thirty-eight".