261686101 has 4 divisors (see below), whose sum is σ = 261933804. Its totient is φ = 261438400.

The previous prime is 261686099. The next prime is 261686129. The reversal of 261686101 is 101686162.

261686101 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 228795876 + 32890225 = 15126^2 + 5735^2 .

It is a cyclic number.

It is not a de Polignac number, because 261686101 - 2¹ = 261686099 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261686141) 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, 122260 + ... + 124381.

It is an arithmetic number, because the mean of its divisors is an integer number (65483451).

Almost surely, 2^261686101 is an apocalyptic number.

It is an amenable number.

261686101 is a deficient number, since it is larger than the sum of its proper divisors (247703).

261686101 is a wasteful number, since it uses less digits than its factorization.

261686101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247702.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 261686101 is about 16176.7147777291. The cubic root of 261686101 is about 639.6271436604.

The spelling of 261686101 in words is "two hundred sixty-one million, six hundred eighty-six thousand, one hundred one".