161643 has 4 divisors (see below), whose sum is σ = 215528. Its totient is φ = 107760.

The previous prime is 161641. The next prime is 161659. The reversal of 161643 is 346161.

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

It is not a de Polignac number, because 161643 - 2¹ = 161641 is a prime.

It is a super-2 number, since 2×161643² = 52256918898, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161641) 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, 26938 + ... + 26943.

It is an arithmetic number, because the mean of its divisors is an integer number (53882).

2¹⁶¹⁶⁴³ is an apocalyptic number.

161643 is a deficient number, since it is larger than the sum of its proper divisors (53885).

161643 is an equidigital number, since it uses as much as digits as its factorization.

161643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53884.

The product of its digits is 432, while the sum is 21.

The square root of 161643 is about 402.0485045365. The cubic root of 161643 is about 54.4735443801.

The spelling of 161643 in words is "one hundred sixty-one thousand, six hundred forty-three".