261288 has 48 divisors (see below), whose sum is σ = 748800. Its totient is φ = 82080.

The previous prime is 261281. The next prime is 261301. The reversal of 261288 is 882162.

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

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (261281) by changing a digit.

261288 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1273 + ... + 1463.

It is an arithmetic number, because the mean of its divisors is an integer number (15600).

2²⁶¹²⁸⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (374400).

261288 is an abundant number, since it is smaller than the sum of its proper divisors (487512).

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

261288 is a wasteful number, since it uses less digits than its factorization.

261288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222 (or 215 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 261288 is about 511.1633789700. The cubic root of 261288 is about 63.9302625801.

The spelling of 261288 in words is "two hundred sixty-one thousand, two hundred eighty-eight".