261231 has 8 divisors (see below), whose sum is σ = 366720. Its totient is φ = 164952.

The previous prime is 261229. The next prime is 261241. The reversal of 261231 is 132162.

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

It is not a de Polignac number, because 261231 - 2¹ = 261229 is a prime.

It is a super-2 number, since 2×261231² = 136483270722, which contains 22 as substring.

261231 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 261231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261241) 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, 2235 + ... + 2348.

It is an arithmetic number, because the mean of its divisors is an integer number (45840).

2²⁶¹²³¹ is an apocalyptic number.

261231 is a deficient number, since it is larger than the sum of its proper divisors (105489).

261231 is a wasteful number, since it uses less digits than its factorization.

261231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4605.

The product of its digits is 72, while the sum is 15.

The square root of 261231 is about 511.1076207610. The cubic root of 261231 is about 63.9256134445.

Adding to 261231 its reverse (132162), we get a palindrome (393393).

The spelling of 261231 in words is "two hundred sixty-one thousand, two hundred thirty-one".