261018720 has 384 divisors, whose sum is σ = 992839680. Its totient is φ = 63866880.

The previous prime is 261018691. The next prime is 261018721. The reversal of 261018720 is 27810162.

261018720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261018721) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3676285 + ... + 3676355.

It is an arithmetic number, because the mean of its divisors is an integer number (2585520).

Almost surely, 2^261018720 is an apocalyptic number.

261018720 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 261018720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (496419840).

261018720 is an abundant number, since it is smaller than the sum of its proper divisors (731820960).

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

261018720 is a wasteful number, since it uses less digits than its factorization.

261018720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155 (or 141 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 261018720 is about 16156.0737804703. The cubic root of 261018720 is about 639.0829313335.

Adding to 261018720 its reverse (27810162), we get a palindrome (288828882).

The spelling of 261018720 in words is "two hundred sixty-one million, eighteen thousand, seven hundred twenty".