161800 has 24 divisors (see below), whose sum is σ = 376650. Its totient is φ = 64640.

The previous prime is 161783. The next prime is 161807. The reversal of 161800 is 8161.

It can be written as a sum of positive squares in 3 ways, for example, as 145924 + 15876 = 382^2 + 126^2 .

It is a cake number, because a cake can be divided into 161800 parts by 99 planar cuts.

It is not an unprimeable number, because it can be changed into a prime (161807) by changing a digit.

161800 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, 205 + ... + 604.

2¹⁶¹⁸⁰⁰ is an apocalyptic number.

161800 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161800 is an abundant number, since it is smaller than the sum of its proper divisors (214850).

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

161800 is a wasteful number, since it uses less digits than its factorization.

161800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 825 (or 816 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 16.

The square root of 161800 is about 402.2437072224. The cubic root of 161800 is about 54.4911749591.

Adding to 161800 its reverse (8161), we get a palindrome (169961).

It can be divided in two parts, 161 and 800, that added together give a square (961 = 31²).

The spelling of 161800 in words is "one hundred sixty-one thousand, eight hundred".