261166666 has 8 divisors (see below), whose sum is σ = 412368480. Its totient is φ = 123710508.

The previous prime is 261166621. The next prime is 261166691. The reversal of 261166666 is 666661162.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3436366 + ... + 3436441.

It is an arithmetic number, because the mean of its divisors is an integer number (51546060).

Almost surely, 2^261166666 is an apocalyptic number.

261166666 is a deficient number, since it is larger than the sum of its proper divisors (151201814).

261166666 is a wasteful number, since it uses less digits than its factorization.

261166666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6872828.

The product of its digits is 93312, while the sum is 40.

The square root of 261166666 is about 16160.6517814103. The cubic root of 261166666 is about 639.2036530775.

The spelling of 261166666 in words is "two hundred sixty-one million, one hundred sixty-six thousand, six hundred sixty-six".