639828049 has 4 divisors (see below), whose sum is σ = 731232064. Its totient is φ = 548424036.

The previous prime is 639828029. The next prime is 639828071. The reversal of 639828049 is 940828936.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 639828049 - 2⁵ = 639828017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 639827993 and 639828011.

It is not an unprimeable number, because it can be changed into a prime (639828029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45701997 + ... + 45702010.

It is an arithmetic number, because the mean of its divisors is an integer number (182808016).

Almost surely, 2^639828049 is an apocalyptic number.

It is an amenable number.

639828049 is a deficient number, since it is larger than the sum of its proper divisors (91404015).

639828049 is an equidigital number, since it uses as much as digits as its factorization.

639828049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91404014.

The product of its (nonzero) digits is 746496, while the sum is 49.

The square root of 639828049 is about 25294.8225730089. The cubic root of 639828049 is about 861.6966905166.

The spelling of 639828049 in words is "six hundred thirty-nine million, eight hundred twenty-eight thousand, forty-nine".