19887149 has 2 divisors, whose sum is σ = 19887150. Its totient is φ = 19887148.

The previous prime is 19887121. The next prime is 19887163. The reversal of 19887149 is 94178891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15264649 + 4622500 = 3907^2 + 2150^2 .

It is an emirp because it is prime and its reverse (94178891) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19887149 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19887169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9943574 + 9943575.

It is an arithmetic number, because the mean of its divisors is an integer number (9943575).

Almost surely, 2^19887149 is an apocalyptic number.

It is an amenable number.

19887149 is a deficient number, since it is larger than the sum of its proper divisors (1).

19887149 is an equidigital number, since it uses as much as digits as its factorization.

19887149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 47.

The square root of 19887149 is about 4459.5009810516. The cubic root of 19887149 is about 270.9302571491.

The spelling of 19887149 in words is "nineteen million, eight hundred eighty-seven thousand, one hundred forty-nine".