1999838549 has 2 divisors, whose sum is σ = 1999838550. Its totient is φ = 1999838548.

The previous prime is 1999838531. The next prime is 1999838573. The reversal of 1999838549 is 9458389991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1000140625 + 999697924 = 31625^2 + 31618^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1999838549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1999838149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999919274 + 999919275.

It is an arithmetic number, because the mean of its divisors is an integer number (999919275).

Almost surely, 2^1999838549 is an apocalyptic number.

It is an amenable number.

1999838549 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999838549 is an equidigital number, since it uses as much as digits as its factorization.

1999838549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25194240, while the sum is 65.

The square root of 1999838549 is about 44719.5544365102. The cubic root of 1999838549 is about 1259.8871463970.

The spelling of 1999838549 in words is "one billion, nine hundred ninety-nine million, eight hundred thirty-eight thousand, five hundred forty-nine".