261263291 has 16 divisors (see below), whose sum is σ = 274687200. Its totient is φ = 248172288.

The previous prime is 261263287. The next prime is 261263297. The reversal of 261263291 is 192362162.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 261263291 - 2² = 261263287 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261263297) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 834551 + ... + 834863.

It is an arithmetic number, because the mean of its divisors is an integer number (17167950).

Almost surely, 2^261263291 is an apocalyptic number.

261263291 is a deficient number, since it is larger than the sum of its proper divisors (13423909).

261263291 is a wasteful number, since it uses less digits than its factorization.

261263291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 718.

The product of its digits is 7776, while the sum is 32.

The square root of 261263291 is about 16163.6410192753. The cubic root of 261263291 is about 639.2824730364.

The spelling of 261263291 in words is "two hundred sixty-one million, two hundred sixty-three thousand, two hundred ninety-one".