19486721 has 2 divisors, whose sum is σ = 19486722. Its totient is φ = 19486720.

The previous prime is 19486703. The next prime is 19486741. The reversal of 19486721 is 12768491.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19044496 + 442225 = 4364^2 + 665^2 .

It is an emirp because it is prime and its reverse (12768491) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19486721 - 2¹⁴ = 19470337 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a nialpdrome in base 11.

It is not a weakly prime, because it can be changed into another prime (19486741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9743360 + 9743361.

It is an arithmetic number, because the mean of its divisors is an integer number (9743361).

Almost surely, 2^19486721 is an apocalyptic number.

It is an amenable number.

19486721 is a deficient number, since it is larger than the sum of its proper divisors (1).

19486721 is an equidigital number, since it uses as much as digits as its factorization.

19486721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192, while the sum is 38.

The square root of 19486721 is about 4414.3766264332. The cubic root of 19486721 is about 269.0995195680.

The spelling of 19486721 in words is "nineteen million, four hundred eighty-six thousand, seven hundred twenty-one".