261155 has 8 divisors (see below), whose sum is σ = 330000. Its totient is φ = 197856.

The previous prime is 261127. The next prime is 261167. The reversal of 261155 is 551162.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261155 is a prime.

It is an unprimeable 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 7 ways as a sum of consecutive naturals, for example, 1280 + ... + 1469.

It is an arithmetic number, because the mean of its divisors is an integer number (41250).

2²⁶¹¹⁵⁵ is an apocalyptic number.

261155 is a deficient number, since it is larger than the sum of its proper divisors (68845).

261155 is a wasteful number, since it uses less digits than its factorization.

261155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2773.

The product of its digits is 300, while the sum is 20.

The square root of 261155 is about 511.0332670189. The cubic root of 261155 is about 63.9194135450.

The spelling of 261155 in words is "two hundred sixty-one thousand, one hundred fifty-five".