261435165 has 16 divisors (see below), whose sum is σ = 420177408. Its totient is φ = 138805056.

The previous prime is 261435157. The next prime is 261435173. The reversal of 261435165 is 561534162.

It is an interprime number because it is at equal distance from previous prime (261435157) and next prime (261435173).

It is not a de Polignac number, because 261435165 - 2³ = 261435157 is a prime.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 35734 + ... + 42423.

It is an arithmetic number, because the mean of its divisors is an integer number (26261088).

Almost surely, 2^261435165 is an apocalyptic number.

It is an amenable number.

261435165 is a deficient number, since it is larger than the sum of its proper divisors (158742243).

261435165 is a wasteful number, since it uses less digits than its factorization.

261435165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78388.

The product of its digits is 21600, while the sum is 33.

The square root of 261435165 is about 16168.9568309152. The cubic root of 261435165 is about 639.4226278841.

The spelling of 261435165 in words is "two hundred sixty-one million, four hundred thirty-five thousand, one hundred sixty-five".