261656717 has 12 divisors (see below), whose sum is σ = 317611296. Its totient is φ = 214525080.

The previous prime is 261656713. The next prime is 261656719. The reversal of 261656717 is 717656162.

It is not a de Polignac number, because 261656717 - 2² = 261656713 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261656713) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 114959 + ... + 117212.

It is an arithmetic number, because the mean of its divisors is an integer number (26467608).

Almost surely, 2^261656717 is an apocalyptic number.

It is an amenable number.

261656717 is a deficient number, since it is larger than the sum of its proper divisors (55954579).

261656717 is a wasteful number, since it uses less digits than its factorization.

261656717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232208 (or 232201 counting only the distinct ones).

The product of its digits is 105840, while the sum is 41.

The square root of 261656717 is about 16175.8065332150. The cubic root of 261656717 is about 639.6032021169.

The spelling of 261656717 in words is "two hundred sixty-one million, six hundred fifty-six thousand, seven hundred seventeen".