261644288 has 84 divisors (see below), whose sum is σ = 564558180. Its totient is φ = 120913920.

The previous prime is 261644281. The next prime is 261644359. The reversal of 261644288 is 882446162.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a nialpdrome in base 16.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261644281) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6381548 + ... + 6381588.

Almost surely, 2^261644288 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 261644288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (282279090).

261644288 is an abundant number, since it is smaller than the sum of its proper divisors (302913892).

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

261644288 is an frugal number, since it uses more digits than its factorization.

261644288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127 (or 62 counting only the distinct ones).

The product of its digits is 147456, while the sum is 41.

The square root of 261644288 is about 16175.4223437906. The cubic root of 261644288 is about 639.5930746566.

The spelling of 261644288 in words is "two hundred sixty-one million, six hundred forty-four thousand, two hundred eighty-eight".