639530497 has 4 divisors (see below), whose sum is σ = 677149956. Its totient is φ = 601911040.

The previous prime is 639530491. The next prime is 639530501. The reversal of 639530497 is 794035936.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 361608256 + 277922241 = 19016^2 + 16671^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639530497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639530491) 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 3 ways as a sum of consecutive naturals, for example, 18809704 + ... + 18809737.

It is an arithmetic number, because the mean of its divisors is an integer number (169287489).

Almost surely, 2^639530497 is an apocalyptic number.

It is an amenable number.

639530497 is a deficient number, since it is larger than the sum of its proper divisors (37619459).

639530497 is a wasteful number, since it uses less digits than its factorization.

639530497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37619458.

The product of its (nonzero) digits is 612360, while the sum is 46.

The square root of 639530497 is about 25288.9402110883. The cubic root of 639530497 is about 861.5630924712.

The spelling of 639530497 in words is "six hundred thirty-nine million, five hundred thirty thousand, four hundred ninety-seven".