261388441 has 2 divisors, whose sum is σ = 261388442. Its totient is φ = 261388440.

The previous prime is 261388433. The next prime is 261388451. The reversal of 261388441 is 144883162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 256640400 + 4748041 = 16020^2 + 2179^2 .

It is a cyclic number.

It is not a de Polignac number, because 261388441 - 2³ = 261388433 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261388441.

It is not a weakly prime, because it can be changed into another prime (261388451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130694220 + 130694221.

It is an arithmetic number, because the mean of its divisors is an integer number (130694221).

Almost surely, 2^261388441 is an apocalyptic number.

It is an amenable number.

261388441 is a deficient number, since it is larger than the sum of its proper divisors (1).

261388441 is an equidigital number, since it uses as much as digits as its factorization.

261388441 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36864, while the sum is 37.

The square root of 261388441 is about 16167.5118988668. The cubic root of 261388441 is about 639.3845328267.

It can be divided in two parts, 261 and 388441, that multiplied together give a palindrome (101383101).

The spelling of 261388441 in words is "two hundred sixty-one million, three hundred eighty-eight thousand, four hundred forty-one".