261660011 has 4 divisors (see below), whose sum is σ = 270682800. Its totient is φ = 252637224.

The previous prime is 261659987. The next prime is 261660013. The reversal of 261660011 is 110066162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 110066162 = 2 ⋅55033081.

It is a cyclic number.

It is not a de Polignac number, because 261660011 - 2¹⁰ = 261658987 is a prime.

It is a super-2 number, since 2×261660011² = 136931922713040242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261660013) 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, 4511351 + ... + 4511408.

It is an arithmetic number, because the mean of its divisors is an integer number (67670700).

Almost surely, 2^261660011 is an apocalyptic number.

261660011 is a deficient number, since it is larger than the sum of its proper divisors (9022789).

261660011 is an equidigital number, since it uses as much as digits as its factorization.

261660011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9022788.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 261660011 is about 16175.9083516197. The cubic root of 261660011 is about 639.6058860968.

The spelling of 261660011 in words is "two hundred sixty-one million, six hundred sixty thousand, eleven".