261026111 has 4 divisors (see below), whose sum is σ = 262338000. Its totient is φ = 259714224.

The previous prime is 261026093. The next prime is 261026153. The reversal of 261026111 is 111620162.

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

It is a cyclic number.

It is not a de Polignac number, because 261026111 - 2¹⁰ = 261025087 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 (261026911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 655646 + ... + 656043.

It is an arithmetic number, because the mean of its divisors is an integer number (65584500).

Almost surely, 2^261026111 is an apocalyptic number.

261026111 is a deficient number, since it is larger than the sum of its proper divisors (1311889).

261026111 is a wasteful number, since it uses less digits than its factorization.

261026111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1311888.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 261026111 is about 16156.3025163557. The cubic root of 261026111 is about 639.0889633624.

Adding to 261026111 its reverse (111620162), we get a palindrome (372646273).

The spelling of 261026111 in words is "two hundred sixty-one million, twenty-six thousand, one hundred eleven".