638596489 has 2 divisors, whose sum is σ = 638596490. Its totient is φ = 638596488.

The previous prime is 638596487. The next prime is 638596529. The reversal of 638596489 is 984695836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 519612025 + 118984464 = 22795^2 + 10908^2 .

It is a cyclic number.

It is not a de Polignac number, because 638596489 - 2¹ = 638596487 is a prime.

Together with 638596487, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (638596487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319298244 + 319298245.

It is an arithmetic number, because the mean of its divisors is an integer number (319298245).

Almost surely, 2^638596489 is an apocalyptic number.

It is an amenable number.

638596489 is a deficient number, since it is larger than the sum of its proper divisors (1).

638596489 is an equidigital number, since it uses as much as digits as its factorization.

638596489 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11197440, while the sum is 58.

The square root of 638596489 is about 25270.4667349062. The cubic root of 638596489 is about 861.1434622947.

The spelling of 638596489 in words is "six hundred thirty-eight million, five hundred ninety-six thousand, four hundred eighty-nine".