178161 has 4 divisors (see below), whose sum is σ = 237552. Its totient is φ = 118772.

The previous prime is 178151. The next prime is 178169. The reversal of 178161 is 161871.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-178161 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (178169) 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, 29691 + ... + 29696.

It is an arithmetic number, because the mean of its divisors is an integer number (59388).

2¹⁷⁸¹⁶¹ is an apocalyptic number.

It is an amenable number.

178161 is a deficient number, since it is larger than the sum of its proper divisors (59391).

178161 is an equidigital number, since it uses as much as digits as its factorization.

178161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59390.

The product of its digits is 336, while the sum is 24.

The square root of 178161 is about 422.0912223679. The cubic root of 178161 is about 56.2692181246.

Subtracting from 178161 its reverse (161871), we obtain a triangular number (16290 = T₁₈₀).

The spelling of 178161 in words is "one hundred seventy-eight thousand, one hundred sixty-one".