639819648 has 320 divisors, whose sum is σ = 2114925120. Its totient is φ = 190771200.

The previous prime is 639819643. The next prime is 639819679. The reversal of 639819648 is 846918936.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 639819594 and 639819603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639819643) 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 39 ways as a sum of consecutive naturals, for example, 6334798 + ... + 6334898.

It is an arithmetic number, because the mean of its divisors is an integer number (6609141).

Almost surely, 2^639819648 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639819648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1057462560).

639819648 is an abundant number, since it is smaller than the sum of its proper divisors (1475105472).

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

639819648 is a wasteful number, since it uses less digits than its factorization.

639819648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187 (or 166 counting only the distinct ones).

The product of its digits is 2239488, while the sum is 54.

The square root of 639819648 is about 25294.6565108127. The cubic root of 639819648 is about 861.6929191150.

The spelling of 639819648 in words is "six hundred thirty-nine million, eight hundred nineteen thousand, six hundred forty-eight".