261158305 has 8 divisors (see below), whose sum is σ = 315678312. Its totient is φ = 207401088.

The previous prime is 261158257. The next prime is 261158329. The reversal of 261158305 is 503851162.

It can be written as a sum of positive squares in 4 ways, for example, as 15421329 + 245736976 = 3927^2 + 15676^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261158305 - 2¹⁵ = 261125537 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 189942 + ... + 191311.

It is an arithmetic number, because the mean of its divisors is an integer number (39459789).

Almost surely, 2^261158305 is an apocalyptic number.

It is an amenable number.

261158305 is a deficient number, since it is larger than the sum of its proper divisors (54520007).

261158305 is a wasteful number, since it uses less digits than its factorization.

261158305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381395.

The product of its (nonzero) digits is 7200, while the sum is 31.

The square root of 261158305 is about 16160.3930954665. The cubic root of 261158305 is about 639.1968318410.

The spelling of 261158305 in words is "two hundred sixty-one million, one hundred fifty-eight thousand, three hundred five".