19998427 has 2 divisors, whose sum is σ = 19998428. Its totient is φ = 19998426.

The previous prime is 19998413. The next prime is 19998479. The reversal of 19998427 is 72489991.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19998427 is a prime.

It is not a weakly prime, because it can be changed into another prime (19998497) 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, 9999213 + 9999214.

It is an arithmetic number, because the mean of its divisors is an integer number (9999214).

Almost surely, 2^19998427 is an apocalyptic number.

19998427 is a deficient number, since it is larger than the sum of its proper divisors (1).

19998427 is an equidigital number, since it uses as much as digits as its factorization.

19998427 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 326592, while the sum is 49.

The square root of 19998427 is about 4471.9600847950. The cubic root of 19998427 is about 271.4346451747.

The spelling of 19998427 in words is "nineteen million, nine hundred ninety-eight thousand, four hundred twenty-seven".