161999999999 has 8 divisors (see below), whose sum is σ = 162130157280. Its totient is φ = 161869888000.

The previous prime is 161999999983. The next prime is 162000000037. The reversal of 161999999999 is 999999999161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161999999999 - 2⁴ = 161999999983 is a prime.

It is a Duffinian number.

161999999999 is a modest number, since divided by 999999 gives 161999 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161999999099) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11267087 + ... + 11281455.

It is an arithmetic number, because the mean of its divisors is an integer number (20266269660).

Almost surely, 2^161999999999 is an apocalyptic number.

161999999999 is a deficient number, since it is larger than the sum of its proper divisors (130157281).

161999999999 is a wasteful number, since it uses less digits than its factorization.

161999999999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22641.

The product of its digits is 2324522934, while the sum is 89.

The spelling of 161999999999 in words is "one hundred sixty-one billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine".