18989923 has 2 divisors, whose sum is σ = 18989924. Its totient is φ = 18989922.

The previous prime is 18989909. The next prime is 18989933. The reversal of 18989923 is 32998981.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18989923 - 2¹³ = 18981731 is a prime.

It is not a weakly prime, because it can be changed into another prime (18989933) 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, 9494961 + 9494962.

It is an arithmetic number, because the mean of its divisors is an integer number (9494962).

Almost surely, 2^18989923 is an apocalyptic number.

18989923 is a deficient number, since it is larger than the sum of its proper divisors (1).

18989923 is an equidigital number, since it uses as much as digits as its factorization.

18989923 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 49.

The square root of 18989923 is about 4357.7428790602. The cubic root of 18989923 is about 266.7929819975.

The spelling of 18989923 in words is "eighteen million, nine hundred eighty-nine thousand, nine hundred twenty-three".