639429678 has 24 divisors (see below), whose sum is σ = 1390591800. Its totient is φ = 212349264.

The previous prime is 639429673. The next prime is 639429761. The reversal of 639429678 is 876924936.

It is a happy number.

639429678 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639429673) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 61188 + ... + 70871.

It is an arithmetic number, because the mean of its divisors is an integer number (57941325).

Almost surely, 2^639429678 is an apocalyptic number.

639429678 is an abundant number, since it is smaller than the sum of its proper divisors (751162122).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

639429678 is a wasteful number, since it uses less digits than its factorization.

639429678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132336 (or 132333 counting only the distinct ones).

The product of its digits is 3919104, while the sum is 54.

The square root of 639429678 is about 25286.9467907852. The cubic root of 639429678 is about 861.5178162909.

The spelling of 639429678 in words is "six hundred thirty-nine million, four hundred twenty-nine thousand, six hundred seventy-eight".