19898609 has 2 divisors, whose sum is σ = 19898610. Its totient is φ = 19898608.

The previous prime is 19898603. The next prime is 19898617. The reversal of 19898609 is 90689891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14992384 + 4906225 = 3872^2 + 2215^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19898609 is a prime.

It is not a weakly prime, because it can be changed into another prime (19898603) 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, 9949304 + 9949305.

It is an arithmetic number, because the mean of its divisors is an integer number (9949305).

Almost surely, 2^19898609 is an apocalyptic number.

It is an amenable number.

19898609 is a deficient number, since it is larger than the sum of its proper divisors (1).

19898609 is an equidigital number, since it uses as much as digits as its factorization.

19898609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 279936, while the sum is 50.

The square root of 19898609 is about 4460.7856931263. The cubic root of 19898609 is about 270.9822884809.

The spelling of 19898609 in words is "nineteen million, eight hundred ninety-eight thousand, six hundred nine".