16539789510721 has 2 divisors, whose sum is σ = 16539789510722. Its totient is φ = 16539789510720.

The previous prime is 16539789510719. The next prime is 16539789510787. The reversal of 16539789510721 is 12701598793561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16470294006321 + 69495504400 = 4058361^2 + 263620^2 .

It is a cyclic number.

It is not a de Polignac number, because 16539789510721 - 2¹ = 16539789510719 is a prime.

Together with 16539789510719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (16539789510221) 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 as a sum of consecutive naturals, namely, 8269894755360 + 8269894755361.

It is an arithmetic number, because the mean of its divisors is an integer number (8269894755361).

Almost surely, 2^{16539789510721} is an apocalyptic number.

It is an amenable number.

16539789510721 is a deficient number, since it is larger than the sum of its proper divisors (1).

16539789510721 is an equidigital number, since it uses as much as digits as its factorization.

16539789510721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28576800, while the sum is 64.

The spelling of 16539789510721 in words is "sixteen trillion, five hundred thirty-nine billion, seven hundred eighty-nine million, five hundred ten thousand, seven hundred twenty-one".