261388 has 12 divisors (see below), whose sum is σ = 462672. Its totient is φ = 129200.

The previous prime is 261379. The next prime is 261389. The reversal of 261388 is 883162.

It is not an unprimeable number, because it can be changed into a prime (261389) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 81 + ... + 727.

It is an arithmetic number, because the mean of its divisors is an integer number (38556).

2²⁶¹³⁸⁸ is an apocalyptic number.

It is an amenable number.

261388 is a deficient number, since it is larger than the sum of its proper divisors (201284).

261388 is a wasteful number, since it uses less digits than its factorization.

261388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 752 (or 750 counting only the distinct ones).

The product of its digits is 2304, while the sum is 28.

The square root of 261388 is about 511.2611856967. The cubic root of 261388 is about 63.9384173249.

It can be divided in two parts, 2613 and 88, that added together give a triangular number (2701 = T₇₃).

The spelling of 261388 in words is "two hundred sixty-one thousand, three hundred eighty-eight".