261155166 has 8 divisors (see below), whose sum is σ = 522310344. Its totient is φ = 87051720.

The previous prime is 261155149. The next prime is 261155189. The reversal of 261155166 is 661551162.

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

261155166 is an admirable number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21762925 + ... + 21762936.

It is an arithmetic number, because the mean of its divisors is an integer number (65288793).

Almost surely, 2^261155166 is an apocalyptic number.

261155166 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

261155166 is a wasteful number, since it uses less digits than its factorization.

261155166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43525866.

The product of its digits is 10800, while the sum is 33.

The square root of 261155166 is about 16160.2959750123. The cubic root of 261155166 is about 639.1942708823.

The spelling of 261155166 in words is "two hundred sixty-one million, one hundred fifty-five thousand, one hundred sixty-six".