261738 has 32 divisors (see below), whose sum is σ = 601920. Its totient is φ = 84240.

The previous prime is 261721. The next prime is 261739. The reversal of 261738 is 837162.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (261739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1933 + ... + 2063.

It is an arithmetic number, because the mean of its divisors is an integer number (18810).

2²⁶¹⁷³⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261738, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (300960).

261738 is an abundant number, since it is smaller than the sum of its proper divisors (340182).

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

261738 is a wasteful number, since it uses less digits than its factorization.

261738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179 (or 173 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 261738 is about 511.6033619905. The cubic root of 261738 is about 63.9669425634.

It can be divided in two parts, 261 and 738, that added together give a palindrome (999).

The spelling of 261738 in words is "two hundred sixty-one thousand, seven hundred thirty-eight".