261078816 has 96 divisors (see below), whose sum is σ = 709466688. Its totient is φ = 84008960.

The previous prime is 261078787. The next prime is 261078817. The reversal of 261078816 is 618870162.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (261078817) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 444475 + ... + 445061.

It is an arithmetic number, because the mean of its divisors is an integer number (7390278).

Almost surely, 2^261078816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261078816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (354733344).

261078816 is an abundant number, since it is smaller than the sum of its proper divisors (448387872).

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

261078816 is a wasteful number, since it uses less digits than its factorization.

261078816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 754 (or 746 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 39.

The square root of 261078816 is about 16157.9335312409. The cubic root of 261078816 is about 639.1319742791.

The spelling of 261078816 in words is "two hundred sixty-one million, seventy-eight thousand, eight hundred sixteen".