639467 has 4 divisors (see below), whose sum is σ = 645240. Its totient is φ = 633696.

The previous prime is 639451. The next prime is 639487. The reversal of 639467 is 764936.

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

It is a cyclic number.

It is not a de Polignac number, because 639467 - 2⁴ = 639451 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2717 + ... + 2942.

It is an arithmetic number, because the mean of its divisors is an integer number (161310).

2⁶³⁹⁴⁶⁷ is an apocalyptic number.

639467 is a deficient number, since it is larger than the sum of its proper divisors (5773).

639467 is a wasteful number, since it uses less digits than its factorization.

639467 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5772.

The product of its digits is 27216, while the sum is 35.

The square root of 639467 is about 799.6668056134. Note that the first 3 decimals coincide. The cubic root of 639467 is about 86.1534577551.

The spelling of 639467 in words is "six hundred thirty-nine thousand, four hundred sixty-seven".