261365731 has 16 divisors (see below), whose sum is σ = 293368320. Its totient is φ = 230813280.

The previous prime is 261365707. The next prime is 261365771. The reversal of 261365731 is 137563162.

It is a cyclic number.

It is not a de Polignac number, because 261365731 - 2¹³ = 261357539 is a prime.

It is a super-2 number, since 2×261365731² = 136624090682328722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261365771) by changing a digit.

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, 70045 + ... + 73681.

It is an arithmetic number, because the mean of its divisors is an integer number (18335520).

Almost surely, 2^261365731 is an apocalyptic number.

261365731 is a deficient number, since it is larger than the sum of its proper divisors (32002589).

261365731 is a wasteful number, since it uses less digits than its factorization.

261365731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3834.

The product of its digits is 22680, while the sum is 34.

The square root of 261365731 is about 16166.8095491968. The cubic root of 261365731 is about 639.3660152477.

The spelling of 261365731 in words is "two hundred sixty-one million, three hundred sixty-five thousand, seven hundred thirty-one".