261882721 has 2 divisors, whose sum is σ = 261882722. Its totient is φ = 261882720.

The previous prime is 261882701. The next prime is 261882779. The reversal of 261882721 is 127288162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 254243025 + 7639696 = 15945^2 + 2764^2 .

It is a cyclic number.

It is not a de Polignac number, because 261882721 - 2⁵ = 261882689 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (261882701) 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 as a sum of consecutive naturals, namely, 130941360 + 130941361.

It is an arithmetic number, because the mean of its divisors is an integer number (130941361).

Almost surely, 2^261882721 is an apocalyptic number.

It is an amenable number.

261882721 is a deficient number, since it is larger than the sum of its proper divisors (1).

261882721 is an equidigital number, since it uses as much as digits as its factorization.

261882721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21504, while the sum is 37.

The square root of 261882721 is about 16182.7908903254. The cubic root of 261882721 is about 639.7872999237.

The spelling of 261882721 in words is "two hundred sixty-one million, eight hundred eighty-two thousand, seven hundred twenty-one".