16578999991 has 2 divisors, whose sum is σ = 16578999992. Its totient is φ = 16578999990.

The previous prime is 16578999949. The next prime is 16579000019. The reversal of 16578999991 is 19999987561.

It is a strong prime.

It is an emirp because it is prime and its reverse (19999987561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16578999991 - 2¹⁷ = 16578868919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16578999901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8289499995 + 8289499996.

It is an arithmetic number, because the mean of its divisors is an integer number (8289499996).

Almost surely, 2^16578999991 is an apocalyptic number.

16578999991 is a deficient number, since it is larger than the sum of its proper divisors (1).

16578999991 is an equidigital number, since it uses as much as digits as its factorization.

16578999991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 99202320, while the sum is 73.

The spelling of 16578999991 in words is "sixteen billion, five hundred seventy-eight million, nine hundred ninety-nine thousand, nine hundred ninety-one".