261543741734635 has 4 divisors (see below), whose sum is σ = 313852490081568. Its totient is φ = 209234993387704.

The previous prime is 261543741734591. The next prime is 261543741734641. The reversal of 261543741734635 is 536437147345162.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261543741734635 - 2¹⁷ = 261543741603563 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26154374173459 + ... + 26154374173468.

It is an arithmetic number, because the mean of its divisors is an integer number (78463122520392).

Almost surely, 2^{261543741734635} is an apocalyptic number.

261543741734635 is a deficient number, since it is larger than the sum of its proper divisors (52308748346933).

261543741734635 is an equidigital number, since it uses as much as digits as its factorization.

261543741734635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52308748346932.

The product of its digits is 152409600, while the sum is 61.

The spelling of 261543741734635 in words is "two hundred sixty-one trillion, five hundred forty-three billion, seven hundred forty-one million, seven hundred thirty-four thousand, six hundred thirty-five".