261588511 has 4 divisors (see below), whose sum is σ = 267154272. Its totient is φ = 256022752.

The previous prime is 261588493. The next prime is 261588517. The reversal of 261588511 is 115885162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 115885162 = 2 ⋅57942581.

It is a cyclic number.

It is not a de Polignac number, because 261588511 - 2¹⁵ = 261555743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261588517) 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 3 ways as a sum of consecutive naturals, for example, 2782810 + ... + 2782903.

It is an arithmetic number, because the mean of its divisors is an integer number (66788568).

Almost surely, 2^261588511 is an apocalyptic number.

261588511 is a deficient number, since it is larger than the sum of its proper divisors (5565761).

261588511 is an equidigital number, since it uses as much as digits as its factorization.

261588511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5565760.

The product of its digits is 19200, while the sum is 37.

The square root of 261588511 is about 16173.6981238058. The cubic root of 261588511 is about 639.5476222110.

The spelling of 261588511 in words is "two hundred sixty-one million, five hundred eighty-eight thousand, five hundred eleven".