261869689 has 2 divisors, whose sum is σ = 261869690. Its totient is φ = 261869688.

The previous prime is 261869677. The next prime is 261869737. The reversal of 261869689 is 986968162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 255744064 + 6125625 = 15992^2 + 2475^2 .

It is a cyclic number.

It is not a de Polignac number, because 261869689 - 2¹³ = 261861497 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (261869389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130934844 + 130934845.

It is an arithmetic number, because the mean of its divisors is an integer number (130934845).

Almost surely, 2^261869689 is an apocalyptic number.

It is an amenable number.

261869689 is a deficient number, since it is larger than the sum of its proper divisors (1).

261869689 is an equidigital number, since it uses as much as digits as its factorization.

261869689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2239488, while the sum is 55.

The square root of 261869689 is about 16182.3882353625. The cubic root of 261869689 is about 639.7766872261.

The spelling of 261869689 in words is "two hundred sixty-one million, eight hundred sixty-nine thousand, six hundred eighty-nine".