261205685 has 16 divisors (see below), whose sum is σ = 343284480. Its totient is φ = 189618240.

The previous prime is 261205657. The next prime is 261205717. The reversal of 261205685 is 586502162.

It is a de Polignac number, because none of the positive numbers 2^k-261205685 is a prime.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 30221 + ... + 37890.

It is an arithmetic number, because the mean of its divisors is an integer number (21455280).

Almost surely, 2^261205685 is an apocalyptic number.

It is an amenable number.

261205685 is a deficient number, since it is larger than the sum of its proper divisors (82078795).

261205685 is a wasteful number, since it uses less digits than its factorization.

261205685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68188.

The product of its (nonzero) digits is 28800, while the sum is 35.

The square root of 261205685 is about 16161.8589586718. The cubic root of 261205685 is about 639.2354844054.

The spelling of 261205685 in words is "two hundred sixty-one million, two hundred five thousand, six hundred eighty-five".