639165989 has 16 divisors (see below), whose sum is σ = 798815616. Its totient is φ = 496843200.

The previous prime is 639165959. The next prime is 639166039. The reversal of 639165989 is 989561936.

It is not a de Polignac number, because 639165989 - 2¹⁶ = 639100453 is a prime.

It is a super-2 number, since 2×639165989² = 817066322988696242, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639165959) 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 in 15 ways as a sum of consecutive naturals, for example, 22559 + ... + 42275.

It is an arithmetic number, because the mean of its divisors is an integer number (49925976).

Almost surely, 2^639165989 is an apocalyptic number.

It is an amenable number.

639165989 is a deficient number, since it is larger than the sum of its proper divisors (159649627).

639165989 is a wasteful number, since it uses less digits than its factorization.

639165989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20156.

The product of its digits is 3149280, while the sum is 56.

The square root of 639165989 is about 25281.7323180197. The cubic root of 639165989 is about 861.3993753251.

The spelling of 639165989 in words is "six hundred thirty-nine million, one hundred sixty-five thousand, nine hundred eighty-nine".