18605989 has 2 divisors, whose sum is σ = 18605990. Its totient is φ = 18605988.

The previous prime is 18605987. The next prime is 18606013. The reversal of 18605989 is 98950681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16265089 + 2340900 = 4033^2 + 1530^2 .

It is an emirp because it is prime and its reverse (98950681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18605989 - 2¹ = 18605987 is a prime.

Together with 18605987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18605981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9302994 + 9302995.

It is an arithmetic number, because the mean of its divisors is an integer number (9302995).

Almost surely, 2^18605989 is an apocalyptic number.

It is an amenable number.

18605989 is a deficient number, since it is larger than the sum of its proper divisors (1).

18605989 is an equidigital number, since it uses as much as digits as its factorization.

18605989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 155520, while the sum is 46.

The square root of 18605989 is about 4313.4660077483. The cubic root of 18605989 is about 264.9827400649.

The spelling of 18605989 in words is "eighteen million, six hundred five thousand, nine hundred eighty-nine".