261358319287 has 4 divisors (see below), whose sum is σ = 281462805400. Its totient is φ = 241253833176.

The previous prime is 261358319237. The next prime is 261358319293. The reversal of 261358319287 is 782913853162.

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 261358319287 - 2¹¹ = 261358317239 is a prime.

It is a super-3 number, since 3×261358319287³ (a number of 35 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261358319207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10052243037 + ... + 10052243062.

It is an arithmetic number, because the mean of its divisors is an integer number (70365701350).

Almost surely, 2^261358319287 is an apocalyptic number.

261358319287 is a deficient number, since it is larger than the sum of its proper divisors (20104486113).

261358319287 is a wasteful number, since it uses less digits than its factorization.

261358319287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20104486112.

The product of its digits is 4354560, while the sum is 55.

The spelling of 261358319287 in words is "two hundred sixty-one billion, three hundred fifty-eight million, three hundred nineteen thousand, two hundred eighty-seven".