161856 has 42 divisors (see below), whose sum is σ = 465582. Its totient is φ = 53760.

The previous prime is 161839. The next prime is 161869. The reversal of 161856 is 658161.

It can be written as a sum of positive squares in only one way, i.e., 147456 + 14400 = 384^2 + 120^2 .

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

161856 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 436 + ... + 716.

2¹⁶¹⁸⁵⁶ is an apocalyptic number.

161856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (232791).

161856 is an abundant number, since it is smaller than the sum of its proper divisors (303726).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161856 is a wasteful number, since it uses less digits than its factorization.

161856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299 (or 286 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 161856 is about 402.3133107418. The cubic root of 161856 is about 54.4974608137.

The spelling of 161856 in words is "one hundred sixty-one thousand, eight hundred fifty-six".