18821849 has 2 divisors, whose sum is σ = 18821850. Its totient is φ = 18821848.

The previous prime is 18821821. The next prime is 18821857. The reversal of 18821849 is 94812881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17909824 + 912025 = 4232^2 + 955^2 .

It is an emirp because it is prime and its reverse (94812881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18821849 - 2¹⁶ = 18756313 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18821819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9410924 + 9410925.

It is an arithmetic number, because the mean of its divisors is an integer number (9410925).

Almost surely, 2^18821849 is an apocalyptic number.

It is an amenable number.

18821849 is a deficient number, since it is larger than the sum of its proper divisors (1).

18821849 is an equidigital number, since it uses as much as digits as its factorization.

18821849 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36864, while the sum is 41.

The square root of 18821849 is about 4338.4154941637. The cubic root of 18821849 is about 266.0035473550.

The spelling of 18821849 in words is "eighteen million, eight hundred twenty-one thousand, eight hundred forty-nine".