261668 has 24 divisors (see below), whose sum is σ = 527520. Its totient is φ = 112320.

The previous prime is 261643. The next prime is 261673. The reversal of 261668 is 866162.

It is a self number, because there is not a number n which added to its sum of digits gives 261668.

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, 680 + ... + 992.

It is an arithmetic number, because the mean of its divisors is an integer number (21980).

2²⁶¹⁶⁶⁸ is an apocalyptic number.

It is an amenable number.

261668 is an abundant number, since it is smaller than the sum of its proper divisors (265852).

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

261668 is a wasteful number, since it uses less digits than its factorization.

261668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347 (or 345 counting only the distinct ones).

The product of its digits is 3456, while the sum is 29.

The square root of 261668 is about 511.5349450429. The cubic root of 261668 is about 63.9612395510.

It can be divided in two parts, 261 and 668, that added together give a palindrome (929).

The spelling of 261668 in words is "two hundred sixty-one thousand, six hundred sixty-eight".