261394240 has 28 divisors (see below), whose sum is σ = 622445796. Its totient is φ = 104557568.

The previous prime is 261394223. The next prime is 261394247. The reversal of 261394240 is 42493162.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 52649536 + 208744704 = 7256^2 + 14448^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261394247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 408109 + ... + 408748.

It is an arithmetic number, because the mean of its divisors is an integer number (22230207).

Almost surely, 2^261394240 is an apocalyptic number.

261394240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261394240 is an abundant number, since it is smaller than the sum of its proper divisors (361051556).

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

261394240 is an equidigital number, since it uses as much as digits as its factorization.

261394240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 816874 (or 816864 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 31.

The square root of 261394240 is about 16167.6912390112. The cubic root of 261394240 is about 639.3892611198.

The spelling of 261394240 in words is "two hundred sixty-one million, three hundred ninety-four thousand, two hundred forty".