18728533 has 2 divisors, whose sum is σ = 18728534. Its totient is φ = 18728532.

The previous prime is 18728503. The next prime is 18728551. The reversal of 18728533 is 33582781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15186609 + 3541924 = 3897^2 + 1882^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18728533 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18728492 and 18728501.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18728503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9364266 + 9364267.

It is an arithmetic number, because the mean of its divisors is an integer number (9364267).

Almost surely, 2^18728533 is an apocalyptic number.

It is an amenable number.

18728533 is a deficient number, since it is larger than the sum of its proper divisors (1).

18728533 is an equidigital number, since it uses as much as digits as its factorization.

18728533 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40320, while the sum is 37.

The square root of 18728533 is about 4327.6475133726. The cubic root of 18728533 is about 265.5632165048.

The spelling of 18728533 in words is "eighteen million, seven hundred twenty-eight thousand, five hundred thirty-three".