261604761487271 has 4 divisors (see below), whose sum is σ = 261622537187352. Its totient is φ = 261586985787192.

The previous prime is 261604761487243. The next prime is 261604761487331. The reversal of 261604761487271 is 172784167406162.

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 261604761487271 - 2¹⁸ = 261604761225127 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 (261604761487241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8887827965 + ... + 8887857398.

It is an arithmetic number, because the mean of its divisors is an integer number (65405634296838).

Almost surely, 2^{261604761487271} is an apocalyptic number.

261604761487271 is a deficient number, since it is larger than the sum of its proper divisors (17775700081).

261604761487271 is a wasteful number, since it uses less digits than its factorization.

261604761487271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17775700080.

The product of its (nonzero) digits is 37933056, while the sum is 62.

The spelling of 261604761487271 in words is "two hundred sixty-one trillion, six hundred four billion, seven hundred sixty-one million, four hundred eighty-seven thousand, two hundred seventy-one".