261567387591 has 8 divisors (see below), whose sum is σ = 349369447920. Its totient is φ = 174071792832.

The previous prime is 261567387577. The next prime is 261567387643. The reversal of 261567387591 is 195783765162.

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

It is not a de Polignac number, because 261567387591 - 2⁷ = 261567387463 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261567387551) 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, 76614400 + ... + 76617813.

It is an arithmetic number, because the mean of its divisors is an integer number (43671180990).

Almost surely, 2^261567387591 is an apocalyptic number.

261567387591 is a deficient number, since it is larger than the sum of its proper divisors (87802060329).

261567387591 is a wasteful number, since it uses less digits than its factorization.

261567387591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153232785.

The product of its digits is 19051200, while the sum is 60.

The spelling of 261567387591 in words is "two hundred sixty-one billion, five hundred sixty-seven million, three hundred eighty-seven thousand, five hundred ninety-one".