639008989 has 2 divisors, whose sum is σ = 639008990. Its totient is φ = 639008988.

The previous prime is 639008957. The next prime is 639009001. The reversal of 639008989 is 989800936.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 513792889 + 125216100 = 22667^2 + 11190^2 .

It is a cyclic number.

It is not a de Polignac number, because 639008989 - 2⁵ = 639008957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639008089) 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, 319504494 + 319504495.

It is an arithmetic number, because the mean of its divisors is an integer number (319504495).

Almost surely, 2^639008989 is an apocalyptic number.

It is an amenable number.

639008989 is a deficient number, since it is larger than the sum of its proper divisors (1).

639008989 is an equidigital number, since it uses as much as digits as its factorization.

639008989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 839808, while the sum is 52.

The square root of 639008989 is about 25278.6271185759. The cubic root of 639008989 is about 861.3288402951.

The spelling of 639008989 in words is "six hundred thirty-nine million, eight thousand, nine hundred eighty-nine".