261656 has 8 divisors (see below), whose sum is σ = 490620. Its totient is φ = 130824.

The previous prime is 261643. The next prime is 261673. The reversal of 261656 is 656162.

It is a tau number, because it is divible by the number of its divisors (8).

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

261656 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 as a sum of consecutive naturals, namely, 16346 + ... + 16361.

2²⁶¹⁶⁵⁶ is an apocalyptic number.

It is an amenable number.

261656 is a deficient number, since it is larger than the sum of its proper divisors (228964).

261656 is a wasteful number, since it uses less digits than its factorization.

261656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32713 (or 32709 counting only the distinct ones).

The product of its digits is 2160, while the sum is 26.

The square root of 261656 is about 511.5232155044. The cubic root of 261656 is about 63.9602617896.

The spelling of 261656 in words is "two hundred sixty-one thousand, six hundred fifty-six".