19809247 has 2 divisors, whose sum is σ = 19809248. Its totient is φ = 19809246.

The previous prime is 19809221. The next prime is 19809259. The reversal of 19809247 is 74290891.

It is a strong prime.

It is an emirp because it is prime and its reverse (74290891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19809247 - 2¹⁵ = 19776479 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 (19809547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9904623 + 9904624.

It is an arithmetic number, because the mean of its divisors is an integer number (9904624).

Almost surely, 2^19809247 is an apocalyptic number.

19809247 is a deficient number, since it is larger than the sum of its proper divisors (1).

19809247 is an equidigital number, since it uses as much as digits as its factorization.

19809247 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 19809247 is about 4450.7580253256. The cubic root of 19809247 is about 270.5760312808.

The spelling of 19809247 in words is "nineteen million, eight hundred nine thousand, two hundred forty-seven".