16581644899 has 2 divisors, whose sum is σ = 16581644900. Its totient is φ = 16581644898.

The previous prime is 16581644873. The next prime is 16581644903. The reversal of 16581644899 is 99844618561.

It is a strong prime.

It is an emirp because it is prime and its reverse (99844618561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16581644899 - 2¹¹ = 16581642851 is a prime.

It is not a weakly prime, because it can be changed into another prime (16581644999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8290822449 + 8290822450.

It is an arithmetic number, because the mean of its divisors is an integer number (8290822450).

Almost surely, 2^16581644899 is an apocalyptic number.

16581644899 is a deficient number, since it is larger than the sum of its proper divisors (1).

16581644899 is an equidigital number, since it uses as much as digits as its factorization.

16581644899 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14929920, while the sum is 61.

The spelling of 16581644899 in words is "sixteen billion, five hundred eighty-one million, six hundred forty-four thousand, eight hundred ninety-nine".