261280165 has 8 divisors (see below), whose sum is σ = 313971840. Its totient is φ = 208733712.

The previous prime is 261280139. The next prime is 261280171. The reversal of 261280165 is 561082162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261280165 - 2⁵ = 261280133 is a prime.

It is a super-4 number, since 4×261280165⁴ (a number of 35 digits) contains 4444 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32305 + ... + 39574.

It is an arithmetic number, because the mean of its divisors is an integer number (39246480).

Almost surely, 2^261280165 is an apocalyptic number.

It is an amenable number.

261280165 is a deficient number, since it is larger than the sum of its proper divisors (52691675).

261280165 is an equidigital number, since it uses as much as digits as its factorization.

261280165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72611.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 261280165 is about 16164.1629848254. The cubic root of 261280165 is about 639.2962356794.

The spelling of 261280165 in words is "two hundred sixty-one million, two hundred eighty thousand, one hundred sixty-five".