161999319 has 4 divisors (see below), whose sum is σ = 215999096. Its totient is φ = 107999544.

The previous prime is 161999311. The next prime is 161999353. The reversal of 161999319 is 913999161.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 161999319 - 2³ = 161999311 is a prime.

It is a super-2 number, since 2×161999319² = 52487558712927522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161999311) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26999884 + ... + 26999889.

It is an arithmetic number, because the mean of its divisors is an integer number (53999774).

Almost surely, 2^161999319 is an apocalyptic number.

161999319 is a deficient number, since it is larger than the sum of its proper divisors (53999777).

161999319 is an equidigital number, since it uses as much as digits as its factorization.

161999319 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53999776.

The product of its digits is 118098, while the sum is 48.

The square root of 161999319 is about 12727.8953091232. The cubic root of 161999319 is about 545.1354139849.

The spelling of 161999319 in words is "one hundred sixty-one million, nine hundred ninety-nine thousand, three hundred nineteen".