261344666 has 8 divisors (see below), whose sum is σ = 427654944. Its totient is φ = 118793020.

The previous prime is 261344623. The next prime is 261344687. The reversal of 261344666 is 666443162.

It is a happy number.

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

It is a super-3 number, since 3×261344666³ (a number of 26 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5939630 + ... + 5939673.

It is an arithmetic number, because the mean of its divisors is an integer number (53456868).

Almost surely, 2^261344666 is an apocalyptic number.

261344666 is a deficient number, since it is larger than the sum of its proper divisors (166310278).

261344666 is a wasteful number, since it uses less digits than its factorization.

261344666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11879316.

The product of its digits is 124416, while the sum is 38.

The square root of 261344666 is about 16166.1580469820. The cubic root of 261344666 is about 639.3488380316.

The spelling of 261344666 in words is "two hundred sixty-one million, three hundred forty-four thousand, six hundred sixty-six".