156181 has 4 divisors (see below), whose sum is σ = 159552. Its totient is φ = 152812.

The previous prime is 156157. The next prime is 156217. The reversal of 156181 is 181651.

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, and also an emirpimes, since its reverse is a distinct semiprime: 181651 = 373 ⋅487.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-156181 is a prime.

It is a super-2 number, since 2×156181² = 48785009522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (156131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1615 + ... + 1708.

It is an arithmetic number, because the mean of its divisors is an integer number (39888).

2¹⁵⁶¹⁸¹ is an apocalyptic number.

It is an amenable number.

156181 is a deficient number, since it is larger than the sum of its proper divisors (3371).

156181 is an equidigital number, since it uses as much as digits as its factorization.

156181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3370.

The product of its digits is 240, while the sum is 22.

The square root of 156181 is about 395.1974190199. The cubic root of 156181 is about 53.8529377638.

The spelling of 156181 in words is "one hundred fifty-six thousand, one hundred eighty-one".