639350489 has 4 divisors (see below), whose sum is σ = 639420324. Its totient is φ = 639280656.

The previous prime is 639350477. The next prime is 639350549. The reversal of 639350489 is 984053936.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 234334864 + 405015625 = 15308^2 + 20125^2 .

It is a cyclic number.

It is not a de Polignac number, because 639350489 - 2⁴ = 639350473 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (639350429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18662 + ... + 40335.

It is an arithmetic number, because the mean of its divisors is an integer number (159855081).

Almost surely, 2^639350489 is an apocalyptic number.

It is an amenable number.

639350489 is a deficient number, since it is larger than the sum of its proper divisors (69835).

639350489 is a wasteful number, since it uses less digits than its factorization.

639350489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69834.

The product of its (nonzero) digits is 699840, while the sum is 47.

The square root of 639350489 is about 25285.3809344451. The cubic root of 639350489 is about 861.4822504561.

The spelling of 639350489 in words is "six hundred thirty-nine million, three hundred fifty thousand, four hundred eighty-nine".