638928533 has 2 divisors, whose sum is σ = 638928534. Its totient is φ = 638928532.

The previous prime is 638928517. The next prime is 638928547. The reversal of 638928533 is 335829836.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 574896529 + 64032004 = 23977^2 + 8002^2 .

It is a cyclic number.

It is not a de Polignac number, because 638928533 - 2⁴ = 638928517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638928583) 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, 319464266 + 319464267.

It is an arithmetic number, because the mean of its divisors is an integer number (319464267).

Almost surely, 2^638928533 is an apocalyptic number.

It is an amenable number.

638928533 is a deficient number, since it is larger than the sum of its proper divisors (1).

638928533 is an equidigital number, since it uses as much as digits as its factorization.

638928533 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 933120, while the sum is 47.

The square root of 638928533 is about 25277.0356845893. The cubic root of 638928533 is about 861.2926895351.

The spelling of 638928533 in words is "six hundred thirty-eight million, nine hundred twenty-eight thousand, five hundred thirty-three".