639431049 has 8 divisors (see below), whose sum is σ = 865300000. Its totient is φ = 419924736.

The previous prime is 639431021. The next prime is 639431053. The reversal of 639431049 is 940134936.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 639431049 - 2¹¹ = 639429001 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 639430998 and 639431016.

It is not an unprimeable number, because it can be changed into a prime (639431059) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1590424 + ... + 1590825.

It is an arithmetic number, because the mean of its divisors is an integer number (108162500).

Almost surely, 2^639431049 is an apocalyptic number.

It is an amenable number.

639431049 is a deficient number, since it is larger than the sum of its proper divisors (225868951).

639431049 is a wasteful number, since it uses less digits than its factorization.

639431049 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3181319.

The product of its (nonzero) digits is 69984, while the sum is 39.

The square root of 639431049 is about 25286.9738996188. The cubic root of 639431049 is about 861.5184320167.

The spelling of 639431049 in words is "six hundred thirty-nine million, four hundred thirty-one thousand, forty-nine".