261435605 has 8 divisors (see below), whose sum is σ = 332177112. Its totient is φ = 196845568.

The previous prime is 261435589. The next prime is 261435607. The reversal of 261435605 is 506534162.

It can be written as a sum of positive squares in 4 ways, for example, as 143017681 + 118417924 = 11959^2 + 10882^2 .

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 261435605 - 2⁴ = 261435589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261435607) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1537772 + ... + 1537941.

It is an arithmetic number, because the mean of its divisors is an integer number (41522139).

Almost surely, 2^261435605 is an apocalyptic number.

It is an amenable number.

261435605 is a deficient number, since it is larger than the sum of its proper divisors (70741507).

261435605 is a wasteful number, since it uses less digits than its factorization.

261435605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3075735.

The product of its (nonzero) digits is 21600, while the sum is 32.

The square root of 261435605 is about 16168.9704372295. The cubic root of 261435605 is about 639.4229866038.

Adding to 261435605 its reverse (506534162), we get a palindrome (767969767).

The spelling of 261435605 in words is "two hundred sixty-one million, four hundred thirty-five thousand, six hundred five".