18939533 has 2 divisors, whose sum is σ = 18939534. Its totient is φ = 18939532.

The previous prime is 18939491. The next prime is 18939551. The reversal of 18939533 is 33593981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16337764 + 2601769 = 4042^2 + 1613^2 .

It is a cyclic number.

It is not a de Polignac number, because 18939533 - 2¹⁶ = 18873997 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18939553) 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, 9469766 + 9469767.

It is an arithmetic number, because the mean of its divisors is an integer number (9469767).

Almost surely, 2^18939533 is an apocalyptic number.

It is an amenable number.

18939533 is a deficient number, since it is larger than the sum of its proper divisors (1).

18939533 is an equidigital number, since it uses as much as digits as its factorization.

18939533 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 87480, while the sum is 41.

The square root of 18939533 is about 4351.9573757104. The cubic root of 18939533 is about 266.5567934510.

The spelling of 18939533 in words is "eighteen million, nine hundred thirty-nine thousand, five hundred thirty-three".