18989387 has 2 divisors, whose sum is σ = 18989388. Its totient is φ = 18989386.

The previous prime is 18989381. The next prime is 18989393. The reversal of 18989387 is 78398981.

It is a balanced prime because it is at equal distance from previous prime (18989381) and next prime (18989393).

It is a cyclic number.

It is not a de Polignac number, because 18989387 - 2¹⁶ = 18923851 is a prime.

It is not a weakly prime, because it can be changed into another prime (18989381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9494693 + 9494694.

It is an arithmetic number, because the mean of its divisors is an integer number (9494694).

Almost surely, 2^18989387 is an apocalyptic number.

18989387 is a deficient number, since it is larger than the sum of its proper divisors (1).

18989387 is an equidigital number, since it uses as much as digits as its factorization.

18989387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 53.

The square root of 18989387 is about 4357.6813788986. The cubic root of 18989387 is about 266.7904718524.

The spelling of 18989387 in words is "eighteen million, nine hundred eighty-nine thousand, three hundred eighty-seven".