161985599 has 2 divisors, whose sum is σ = 161985600. Its totient is φ = 161985598.

The previous prime is 161985589. The next prime is 161985631. The reversal of 161985599 is 995589161.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161985599 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 161985599.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161985559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80992799 + 80992800.

It is an arithmetic number, because the mean of its divisors is an integer number (80992800).

Almost surely, 2^161985599 is an apocalyptic number.

161985599 is a deficient number, since it is larger than the sum of its proper divisors (1).

161985599 is an equidigital number, since it uses as much as digits as its factorization.

161985599 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 874800, while the sum is 53.

The square root of 161985599 is about 12727.3563240761. The cubic root of 161985599 is about 545.1200240662.

The spelling of 161985599 in words is "one hundred sixty-one million, nine hundred eighty-five thousand, five hundred ninety-nine".