261245072161 has 8 divisors (see below), whose sum is σ = 270028252800. Its totient is φ = 252607068240.

The previous prime is 261245072149. The next prime is 261245072191. The reversal of 261245072161 is 161270542162.

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 261245072161 - 2⁹ = 261245071649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261245072161.

It is not an unprimeable number, because it can be changed into a prime (261245072191) 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, 36290521 + ... + 36297718.

It is an arithmetic number, because the mean of its divisors is an integer number (33753531600).

Almost surely, 2^261245072161 is an apocalyptic number.

It is an amenable number.

261245072161 is a deficient number, since it is larger than the sum of its proper divisors (8783180639).

261245072161 is an equidigital number, since it uses as much as digits as its factorization.

261245072161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72588359.

The product of its (nonzero) digits is 40320, while the sum is 37.

The spelling of 261245072161 in words is "two hundred sixty-one billion, two hundred forty-five million, seventy-two thousand, one hundred sixty-one".