261681934964 has 24 divisors (see below), whose sum is σ = 461197007040. Its totient is φ = 129913956864.

The previous prime is 261681934963. The next prime is 261681934991. The reversal of 261681934964 is 469439186162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261681934963) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 79697 + ... + 727815.

It is an arithmetic number, because the mean of its divisors is an integer number (19216541960).

Almost surely, 2^261681934964 is an apocalyptic number.

It is an amenable number.

261681934964 is a deficient number, since it is larger than the sum of its proper divisors (199515072076).

261681934964 is a wasteful number, since it uses less digits than its factorization.

261681934964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 648839 (or 648837 counting only the distinct ones).

The product of its digits is 13436928, while the sum is 59.

The spelling of 261681934964 in words is "two hundred sixty-one billion, six hundred eighty-one million, nine hundred thirty-four thousand, nine hundred sixty-four".