161231 has 8 divisors (see below), whose sum is σ = 190464. Its totient is φ = 133560.

The previous prime is 161221. The next prime is 161233. The reversal of 161231 is 132161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 161231 - 2⁶ = 161167 is a prime.

It is a super-2 number, since 2×161231² = 51990870722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161233) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 155 + ... + 588.

It is an arithmetic number, because the mean of its divisors is an integer number (23808).

2¹⁶¹²³¹ is an apocalyptic number.

161231 is a deficient number, since it is larger than the sum of its proper divisors (29233).

161231 is an equidigital number, since it uses as much as digits as its factorization.

161231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 781.

The product of its digits is 36, while the sum is 14.

The square root of 161231 is about 401.5358016416. The cubic root of 161231 is about 54.4272237946.

Adding to 161231 its reverse (132161), we get a palindrome (293392).

The spelling of 161231 in words is "one hundred sixty-one thousand, two hundred thirty-one".