19818049 has 4 divisors (see below), whose sum is σ = 20501460. Its totient is φ = 19134640.

The previous prime is 19818031. The next prime is 19818059. The reversal of 19818049 is 94081891.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13727025 + 6091024 = 3705^2 + 2468^2 .

It is a cyclic number.

It is not a de Polignac number, because 19818049 - 2²³ = 11429441 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19818059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 341662 + ... + 341719.

It is an arithmetic number, because the mean of its divisors is an integer number (5125365).

Almost surely, 2^19818049 is an apocalyptic number.

It is an amenable number.

19818049 is a deficient number, since it is larger than the sum of its proper divisors (683411).

19818049 is an equidigital number, since it uses as much as digits as its factorization.

19818049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 683410.

The product of its (nonzero) digits is 20736, while the sum is 40.

The square root of 19818049 is about 4451.7467358330. The cubic root of 19818049 is about 270.6161010787.

The spelling of 19818049 in words is "nineteen million, eight hundred eighteen thousand, forty-nine".