639066649 has 12 divisors (see below), whose sum is σ = 712788076. Its totient is φ = 569556288.

The previous prime is 639066619. The next prime is 639066677. The reversal of 639066649 is 946660936.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 141776649 + 497290000 = 11907^2 + 22300^2 .

It is not a de Polignac number, because 639066649 - 2⁹ = 639066137 is a prime.

It is not an unprimeable number, because it can be changed into a prime (639066619) 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 11 ways as a sum of consecutive naturals, for example, 18294 + ... + 40159.

Almost surely, 2^639066649 is an apocalyptic number.

It is an amenable number.

639066649 is a deficient number, since it is larger than the sum of its proper divisors (73721427).

639066649 is a wasteful number, since it uses less digits than its factorization.

639066649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58524 (or 58495 counting only the distinct ones).

The product of its (nonzero) digits is 1259712, while the sum is 49.

The square root of 639066649 is about 25279.7675820012. The cubic root of 639066649 is about 861.3547464134.

The spelling of 639066649 in words is "six hundred thirty-nine million, sixty-six thousand, six hundred forty-nine".