19873409 has 2 divisors, whose sum is σ = 19873410. Its totient is φ = 19873408.

The previous prime is 19873379. The next prime is 19873421. The reversal of 19873409 is 90437891.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18318400 + 1555009 = 4280^2 + 1247^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19873409 is a prime.

It is not a weakly prime, because it can be changed into another prime (19873429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9936704 + 9936705.

It is an arithmetic number, because the mean of its divisors is an integer number (9936705).

Almost surely, 2^19873409 is an apocalyptic number.

It is an amenable number.

19873409 is a deficient number, since it is larger than the sum of its proper divisors (1).

19873409 is an equidigital number, since it uses as much as digits as its factorization.

19873409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54432, while the sum is 41.

The square root of 19873409 is about 4457.9601837612. The cubic root of 19873409 is about 270.8678476777.

The spelling of 19873409 in words is "nineteen million, eight hundred seventy-three thousand, four hundred nine".