261665027 has 16 divisors (see below), whose sum is σ = 289145472. Its totient is φ = 235284480.

The previous prime is 261665023. The next prime is 261665029. The reversal of 261665027 is 720566162.

It is a cyclic number.

It is not a de Polignac number, because 261665027 - 2² = 261665023 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261665023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 146363 + ... + 148139.

It is an arithmetic number, because the mean of its divisors is an integer number (18071592).

Almost surely, 2^261665027 is an apocalyptic number.

261665027 is a deficient number, since it is larger than the sum of its proper divisors (27480445).

261665027 is a wasteful number, since it uses less digits than its factorization.

261665027 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2078.

The product of its (nonzero) digits is 30240, while the sum is 35.

The square root of 261665027 is about 16176.0633962655. The cubic root of 261665027 is about 639.6099731340.

The spelling of 261665027 in words is "two hundred sixty-one million, six hundred sixty-five thousand, twenty-seven".