261941005 has 8 divisors (see below), whose sum is σ = 321996024. Its totient is φ = 204441600.

The previous prime is 261940969. The next prime is 261941023. The reversal of 261941005 is 500149162.

It can be written as a sum of positive squares in 4 ways, for example, as 21473956 + 240467049 = 4634^2 + 15507^2 .

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

It is not a de Polignac number, because 261941005 - 2⁹ = 261940493 is a prime.

It is a super-2 number, since 2×261941005² = 137226180200820050, which contains 22 as substring.

It is a Duffinian number.

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 7 ways as a sum of consecutive naturals, for example, 638676 + ... + 639085.

It is an arithmetic number, because the mean of its divisors is an integer number (40249503).

Almost surely, 2^261941005 is an apocalyptic number.

It is an amenable number.

261941005 is a deficient number, since it is larger than the sum of its proper divisors (60055019).

261941005 is a wasteful number, since it uses less digits than its factorization.

261941005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1277807.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 261941005 is about 16184.5915920050. The cubic root of 261941005 is about 639.8347595866.

The spelling of 261941005 in words is "two hundred sixty-one million, nine hundred forty-one thousand, five".