261127505 has 4 divisors (see below), whose sum is σ = 313353012. Its totient is φ = 208902000.

The previous prime is 261127501. The next prime is 261127511. The reversal of 261127505 is 505721162.

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 43771456 + 217356049 = 6616^2 + 14743^2 .

It is not a de Polignac number, because 261127505 - 2² = 261127501 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261127501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26112746 + ... + 26112755.

It is an arithmetic number, because the mean of its divisors is an integer number (78338253).

Almost surely, 2^261127505 is an apocalyptic number.

It is an amenable number.

261127505 is a deficient number, since it is larger than the sum of its proper divisors (52225507).

261127505 is an equidigital number, since it uses as much as digits as its factorization.

261127505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52225506.

The product of its (nonzero) digits is 4200, while the sum is 29.

The square root of 261127505 is about 16159.4401202517. The cubic root of 261127505 is about 639.1717027194.

Adding to 261127505 its reverse (505721162), we get a palindrome (766848667).

The spelling of 261127505 in words is "two hundred sixty-one million, one hundred twenty-seven thousand, five hundred five".