261358467840 has 648 divisors, whose sum is σ = 994085623440. Its totient is φ = 63310528512.

The previous prime is 261358467817. The next prime is 261358467847. The reversal of 261358467840 is 48764853162.

It is a happy number.

261358467840 is a `hidden beast` number, since 2 + 6 + 13 + 584 + 6 + 7 + 8 + 40 = 666.

261358467840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (261358467847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 96547767 + ... + 96550473.

Almost surely, 2^261358467840 is an apocalyptic number.

261358467840 is a gapful number since it is divisible by the number (20) 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 261358467840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (497042811720).

261358467840 is an abundant number, since it is smaller than the sum of its proper divisors (732727155600).

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

261358467840 is a wasteful number, since it uses less digits than its factorization.

261358467840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2797 (or 2763 counting only the distinct ones).

The product of its (nonzero) digits is 7741440, while the sum is 54.

The spelling of 261358467840 in words is "two hundred sixty-one billion, three hundred fifty-eight million, four hundred sixty-seven thousand, eight hundred forty".