261681427568 has 20 divisors (see below), whose sum is σ = 553099381368. Its totient is φ = 118946103360.

The previous prime is 261681427543. The next prime is 261681427591. The reversal of 261681427568 is 865724186162.

It is a congruent 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, 743412971 + ... + 743413322.

Almost surely, 2^261681427568 is an apocalyptic number.

It is an amenable number.

261681427568 is an abundant number, since it is smaller than the sum of its proper divisors (291417953800).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261681427568 is a wasteful number, since it uses less digits than its factorization.

261681427568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1486826312 (or 1486826306 counting only the distinct ones).

The product of its digits is 7741440, while the sum is 56.

The spelling of 261681427568 in words is "two hundred sixty-one billion, six hundred eighty-one million, four hundred twenty-seven thousand, five hundred sixty-eight".