261864288 has 72 divisors (see below), whose sum is σ = 851065488. Its totient is φ = 74817792.

The previous prime is 261864271. The next prime is 261864301. The reversal of 261864288 is 882468162.

261864288 is a `hidden beast` number, since 2 + 618 + 6 + 4 + 28 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

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 11 ways as a sum of consecutive naturals, for example, 62931 + ... + 66962.

It is an arithmetic number, because the mean of its divisors is an integer number (11820354).

Almost surely, 2^261864288 is an apocalyptic number.

261864288 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

261864288 is an abundant number, since it is smaller than the sum of its proper divisors (589201200).

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

261864288 is a wasteful number, since it uses less digits than its factorization.

261864288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129916 (or 129905 counting only the distinct ones).

The product of its digits is 294912, while the sum is 45.

The square root of 261864288 is about 16182.2213555494. The cubic root of 261864288 is about 639.7722887819.

The spelling of 261864288 in words is "two hundred sixty-one million, eight hundred sixty-four thousand, two hundred eighty-eight".