261101205 has 64 divisors (see below), whose sum is σ = 475668480. Its totient is φ = 135862272.

The previous prime is 261101143. The next prime is 261101213. The reversal of 261101205 is 502101162.

It is not a de Polignac number, because 261101205 - 2¹⁷ = 260970133 is a prime.

It is a Curzon number.

It is a congruent number.

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 63 ways as a sum of consecutive naturals, for example, 1662987 + ... + 1663143.

It is an arithmetic number, because the mean of its divisors is an integer number (7432320).

Almost surely, 2^261101205 is an apocalyptic number.

It is an amenable number.

261101205 is a deficient number, since it is larger than the sum of its proper divisors (214567275).

261101205 is a wasteful number, since it uses less digits than its factorization.

261101205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395 (or 389 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 261101205 is about 16158.6263339431. The cubic root of 261101205 is about 639.1502434963.

Adding to 261101205 its reverse (502101162), we get a palindrome (763202367).

The spelling of 261101205 in words is "two hundred sixty-one million, one hundred one thousand, two hundred five".