1999904549 has 2 divisors, whose sum is σ = 1999904550. Its totient is φ = 1999904548.

The previous prime is 1999904537. The next prime is 1999904561. The reversal of 1999904549 is 9454099991.

It is a balanced prime because it is at equal distance from previous prime (1999904537) and next prime (1999904561).

It can be written as a sum of positive squares in only one way, i.e., 1966922500 + 32982049 = 44350^2 + 5743^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999904549 - 2²⁸ = 1731469093 is a prime.

It is a super-5 number, since 5×1999904549⁵ (a number of 48 digits) contains 55555 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1999900549) 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, 999952274 + 999952275.

It is an arithmetic number, because the mean of its divisors is an integer number (999952275).

Almost surely, 2^1999904549 is an apocalyptic number.

It is an amenable number.

1999904549 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999904549 is an equidigital number, since it uses as much as digits as its factorization.

1999904549 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4723920, while the sum is 59.

The square root of 1999904549 is about 44720.2923626400. The cubic root of 1999904549 is about 1259.9010061220.

The spelling of 1999904549 in words is "one billion, nine hundred ninety-nine million, nine hundred four thousand, five hundred forty-nine".