19785149 has 2 divisors, whose sum is σ = 19785150. Its totient is φ = 19785148.

The previous prime is 19785131. The next prime is 19785169. The reversal of 19785149 is 94158791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17556100 + 2229049 = 4190^2 + 1493^2 .

It is an emirp because it is prime and its reverse (94158791) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19785149 - 2⁸ = 19784893 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19785169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9892574 + 9892575.

It is an arithmetic number, because the mean of its divisors is an integer number (9892575).

Almost surely, 2^19785149 is an apocalyptic number.

It is an amenable number.

19785149 is a deficient number, since it is larger than the sum of its proper divisors (1).

19785149 is an equidigital number, since it uses as much as digits as its factorization.

19785149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 44.

The square root of 19785149 is about 4448.0500222007. The cubic root of 19785149 is about 270.4662679467.

The spelling of 19785149 in words is "nineteen million, seven hundred eighty-five thousand, one hundred forty-nine".