261147505 has 4 divisors (see below), whose sum is σ = 313377012. Its totient is φ = 208918000.

The previous prime is 261147493. The next prime is 261147521. The reversal of 261147505 is 505741162.

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

It can be written as a sum of positive squares in 2 ways, for example, as 33258289 + 227889216 = 5767^2 + 15096^2 .

It is not a de Polignac number, because 261147505 - 2⁵ = 261147473 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26114746 + ... + 26114755.

It is an arithmetic number, because the mean of its divisors is an integer number (78344253).

Almost surely, 2^261147505 is an apocalyptic number.

It is an amenable number.

261147505 is a deficient number, since it is larger than the sum of its proper divisors (52229507).

261147505 is an equidigital number, since it uses as much as digits as its factorization.

261147505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52229506.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 261147505 is about 16160.0589417242. The cubic root of 261147505 is about 639.1880205558.

Adding to 261147505 its reverse (505741162), we get a palindrome (766888667).

The spelling of 261147505 in words is "two hundred sixty-one million, one hundred forty-seven thousand, five hundred five".