1938999809 has 2 divisors, whose sum is σ = 1938999810. Its totient is φ = 1938999808.

The previous prime is 1938999773. The next prime is 1938999841. The reversal of 1938999809 is 9089998391.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1214313409 + 724686400 = 34847^2 + 26920^2 .

It is a cyclic number.

It is not a de Polignac number, because 1938999809 - 2⁸ = 1938999553 is a prime.

It is not a weakly prime, because it can be changed into another prime (1938999409) 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, 969499904 + 969499905.

It is an arithmetic number, because the mean of its divisors is an integer number (969499905).

Almost surely, 2^1938999809 is an apocalyptic number.

It is an amenable number.

1938999809 is a deficient number, since it is larger than the sum of its proper divisors (1).

1938999809 is an equidigital number, since it uses as much as digits as its factorization.

1938999809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11337408, while the sum is 65.

The square root of 1938999809 is about 44034.0755438331. The cubic root of 1938999809 is about 1246.9793322530.

The spelling of 1938999809 in words is "one billion, nine hundred thirty-eight million, nine hundred ninety-nine thousand, eight hundred nine".