16504644521 has 2 divisors, whose sum is σ = 16504644522. Its totient is φ = 16504644520.

The previous prime is 16504644509. The next prime is 16504644547. The reversal of 16504644521 is 12544640561.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16470128896 + 34515625 = 128336^2 + 5875^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16504644521 is a prime.

It is not a weakly prime, because it can be changed into another prime (16504644581) 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, 8252322260 + 8252322261.

It is an arithmetic number, because the mean of its divisors is an integer number (8252322261).

Almost surely, 2^16504644521 is an apocalyptic number.

It is an amenable number.

16504644521 is a deficient number, since it is larger than the sum of its proper divisors (1).

16504644521 is an equidigital number, since it uses as much as digits as its factorization.

16504644521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 115200, while the sum is 38.

The spelling of 16504644521 in words is "sixteen billion, five hundred four million, six hundred forty-four thousand, five hundred twenty-one".