18889999 has 2 divisors, whose sum is σ = 18890000. Its totient is φ = 18889998.

The previous prime is 18889993. The next prime is 18890021. The reversal of 18889999 is 99998881.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18889999 - 2⁹ = 18889487 is a prime.

18889999 is a modest number, since divided by 9999 gives 1888 as remainder.

It is a plaindrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18889993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9444999 + 9445000.

It is an arithmetic number, because the mean of its divisors is an integer number (9445000).

Almost surely, 2^18889999 is an apocalyptic number.

18889999 is a deficient number, since it is larger than the sum of its proper divisors (1).

18889999 is an equidigital number, since it uses as much as digits as its factorization.

18889999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3359232, while the sum is 61.

The square root of 18889999 is about 4346.2626473788. The cubic root of 18889999 is about 266.3242084875.

The spelling of 18889999 in words is "eighteen million, eight hundred eighty-nine thousand, nine hundred ninety-nine".