261800028784 has 20 divisors (see below), whose sum is σ = 579700063984. Its totient is φ = 112200012288.

The previous prime is 261800028733. The next prime is 261800028863. The reversal of 261800028784 is 487820008162.

It is a happy number.

It is a super-4 number, since 4×261800028784⁴ (a number of 47 digits) contains 4444 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1168750017 + ... + 1168750240.

Almost surely, 2^261800028784 is an apocalyptic number.

It is an amenable number.

261800028784 is an abundant number, since it is smaller than the sum of its proper divisors (317900035200).

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

261800028784 is a wasteful number, since it uses less digits than its factorization.

261800028784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2337500272 (or 2337500266 counting only the distinct ones).

The product of its (nonzero) digits is 344064, while the sum is 46.

The spelling of 261800028784 in words is "two hundred sixty-one billion, eight hundred million, twenty-eight thousand, seven hundred eighty-four".