261178 has 4 divisors (see below), whose sum is σ = 391770. Its totient is φ = 130588.

The previous prime is 261169. The next prime is 261223. The reversal of 261178 is 871162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 233289 + 27889 = 483^2 + 167^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65293 + ... + 65296.

2²⁶¹¹⁷⁸ is an apocalyptic number.

261178 is a deficient number, since it is larger than the sum of its proper divisors (130592).

261178 is a wasteful number, since it uses less digits than its factorization.

261178 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130591.

The product of its digits is 672, while the sum is 25.

The square root of 261178 is about 511.0557699508. The cubic root of 261178 is about 63.9212899573.

It can be divided in two parts, 26 and 1178, that multiplied together give a triangular number (30628 = T₂₄₇).

The spelling of 261178 in words is "two hundred sixty-one thousand, one hundred seventy-eight".