18909623 has 2 divisors, whose sum is σ = 18909624. Its totient is φ = 18909622.

The previous prime is 18909619. The next prime is 18909629. The reversal of 18909623 is 32690981.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18909623 - 2² = 18909619 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18909629) 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, 9454811 + 9454812.

It is an arithmetic number, because the mean of its divisors is an integer number (9454812).

Almost surely, 2^18909623 is an apocalyptic number.

18909623 is a deficient number, since it is larger than the sum of its proper divisors (1).

18909623 is an equidigital number, since it uses as much as digits as its factorization.

18909623 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 18909623 is about 4348.5196331625. The cubic root of 18909623 is about 266.4164007900.

The spelling of 18909623 in words is "eighteen million, nine hundred nine thousand, six hundred twenty-three".