639777009 has 16 divisors (see below), whose sum is σ = 859972032. Its totient is φ = 423062208.

The previous prime is 639777007. The next prime is 639777011. The reversal of 639777009 is 900777936.

It is an interprime number because it is at equal distance from previous prime (639777007) and next prime (639777011).

It is not a de Polignac number, because 639777009 - 2¹ = 639777007 is a prime.

It is not an unprimeable number, because it can be changed into a prime (639777007) 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, 270259 + ... + 272615.

It is an arithmetic number, because the mean of its divisors is an integer number (53748252).

Almost surely, 2^639777009 is an apocalyptic number.

It is an amenable number.

639777009 is a deficient number, since it is larger than the sum of its proper divisors (220195023).

639777009 is a wasteful number, since it uses less digits than its factorization.

639777009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3056.

The product of its (nonzero) digits is 500094, while the sum is 48.

The square root of 639777009 is about 25293.8136507724. The cubic root of 639777009 is about 861.6737769808.

The spelling of 639777009 in words is "six hundred thirty-nine million, seven hundred seventy-seven thousand, nine".