261144 has 80 divisors (see below), whose sum is σ = 813120. Its totient is φ = 77760.

The previous prime is 261127. The next prime is 261167. The reversal of 261144 is 441162.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is an Ulam number.

It is a nialpdrome in base 6.

It is a zygodrome in base 2.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 261144.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 8409 + ... + 8439.

It is an arithmetic number, because the mean of its divisors is an integer number (10164).

2²⁶¹¹⁴⁴ is an apocalyptic number.

261144 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (406560).

261144 is an abundant number, since it is smaller than the sum of its proper divisors (551976).

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

261144 is a wasteful number, since it uses less digits than its factorization.

261144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62 (or 49 counting only the distinct ones).

The product of its digits is 192, while the sum is 18.

The square root of 261144 is about 511.0225043968. The cubic root of 261144 is about 63.9185160915.

Adding to 261144 its sum of digits (18), we get a palindrome (261162).

The spelling of 261144 in words is "two hundred sixty-one thousand, one hundred forty-four".