261819799 has 2 divisors, whose sum is σ = 261819800. Its totient is φ = 261819798.

The previous prime is 261819797. The next prime is 261819827. The reversal of 261819799 is 997918162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261819799 - 2¹ = 261819797 is a prime.

Together with 261819797, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261819797) 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, 130909899 + 130909900.

It is an arithmetic number, because the mean of its divisors is an integer number (130909900).

Almost surely, 2^261819799 is an apocalyptic number.

261819799 is a deficient number, since it is larger than the sum of its proper divisors (1).

261819799 is an equidigital number, since it uses as much as digits as its factorization.

261819799 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 489888, while the sum is 52.

The square root of 261819799 is about 16180.8466712963. The cubic root of 261819799 is about 639.7360557117.

The spelling of 261819799 in words is "two hundred sixty-one million, eight hundred nineteen thousand, seven hundred ninety-nine".