261816899 has 2 divisors, whose sum is σ = 261816900. Its totient is φ = 261816898.

The previous prime is 261816883. The next prime is 261816911. The reversal of 261816899 is 998618162.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261816899 - 2⁴ = 261816883 is a prime.

It is not a weakly prime, because it can be changed into another prime (261816859) 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, 130908449 + 130908450.

It is an arithmetic number, because the mean of its divisors is an integer number (130908450).

Almost surely, 2^261816899 is an apocalyptic number.

261816899 is a deficient number, since it is larger than the sum of its proper divisors (1).

261816899 is an equidigital number, since it uses as much as digits as its factorization.

261816899 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 373248, while the sum is 50.

The square root of 261816899 is about 16180.7570589265. The cubic root of 261816899 is about 639.7336937291.

The spelling of 261816899 in words is "two hundred sixty-one million, eight hundred sixteen thousand, eight hundred ninety-nine".