18989728 has 12 divisors (see below), whose sum is σ = 37386090. Its totient is φ = 9494848.

The previous prime is 18989713. The next prime is 18989767. The reversal of 18989728 is 82798981.

It can be written as a sum of positive squares in only one way, i.e., 10061584 + 8928144 = 3172^2 + 2988^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 296683 + ... + 296746.

Almost surely, 2^18989728 is an apocalyptic number.

It is an amenable number.

18989728 is a deficient number, since it is larger than the sum of its proper divisors (18396362).

18989728 is an equidigital number, since it uses as much as digits as its factorization.

18989728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 593439 (or 593431 counting only the distinct ones).

The product of its digits is 580608, while the sum is 52.

The square root of 18989728 is about 4357.7205050347. The cubic root of 18989728 is about 266.7920687972.

The spelling of 18989728 in words is "eighteen million, nine hundred eighty-nine thousand, seven hundred twenty-eight".