16520221787 has 2 divisors, whose sum is σ = 16520221788. Its totient is φ = 16520221786.

The previous prime is 16520221673. The next prime is 16520221819. The reversal of 16520221787 is 78712202561.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 16520221787 - 2¹⁰ = 16520220763 is a prime.

It is not a weakly prime, because it can be changed into another prime (16526221787) 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, 8260110893 + 8260110894.

It is an arithmetic number, because the mean of its divisors is an integer number (8260110894).

Almost surely, 2^16520221787 is an apocalyptic number.

16520221787 is a deficient number, since it is larger than the sum of its proper divisors (1).

16520221787 is an equidigital number, since it uses as much as digits as its factorization.

16520221787 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 94080, while the sum is 41.

The spelling of 16520221787 in words is "sixteen billion, five hundred twenty million, two hundred twenty-one thousand, seven hundred eighty-seven".