261144720 has 120 divisors (see below), whose sum is σ = 880229376. Its totient is φ = 69383424.

The previous prime is 261144673. The next prime is 261144749. The reversal of 261144720 is 27441162.

261144720 is a `hidden beast` number, since 2 + 611 + 4 + 47 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 275287 + ... + 276233.

Almost surely, 2^261144720 is an apocalyptic number.

261144720 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 261144720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (440114688).

261144720 is an abundant number, since it is smaller than the sum of its proper divisors (619084656).

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

261144720 is a wasteful number, since it uses less digits than its factorization.

261144720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1349 (or 1340 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 261144720 is about 16159.9727722543. The cubic root of 261144720 is about 639.1857483470.

Adding to 261144720 its reverse (27441162), we get a palindrome (288585882).

The spelling of 261144720 in words is "two hundred sixty-one million, one hundred forty-four thousand, seven hundred twenty".