261656166 has 8 divisors (see below), whose sum is σ = 523312344. Its totient is φ = 87218720.

The previous prime is 261656159. The next prime is 261656167. The reversal of 261656166 is 661656162.

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

261656166 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261656167) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21804675 + ... + 21804686.

It is an arithmetic number, because the mean of its divisors is an integer number (65414043).

Almost surely, 2^261656166 is an apocalyptic number.

261656166 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.

261656166 is a wasteful number, since it uses less digits than its factorization.

261656166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43609366.

The product of its digits is 77760, while the sum is 39.

The square root of 261656166 is about 16175.7895015978. The cubic root of 261656166 is about 639.6027531551.

The spelling of 261656166 in words is "two hundred sixty-one million, six hundred fifty-six thousand, one hundred sixty-six".