261334641568 has 768 divisors, whose sum is σ = 751074508800. Its totient is φ = 88058880000.

The previous prime is 261334641517. The next prime is 261334641587. The reversal of 261334641568 is 865146433162.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1994920863 + ... + 1994920993.

It is an arithmetic number, because the mean of its divisors is an integer number (977961600).

Almost surely, 2^261334641568 is an apocalyptic number.

261334641568 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261334641568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (375537254400).

261334641568 is an abundant number, since it is smaller than the sum of its proper divisors (489739867232).

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

261334641568 is a wasteful number, since it uses less digits than its factorization.

261334641568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258 (or 236 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 49.

The spelling of 261334641568 in words is "two hundred sixty-one billion, three hundred thirty-four million, six hundred forty-one thousand, five hundred sixty-eight".