639247 has 16 divisors (see below), whose sum is σ = 783360. Its totient is φ = 510048.

The previous prime is 639211. The next prime is 639253. The reversal of 639247 is 742936.

It is not a de Polignac number, because 639247 - 2¹¹ = 637199 is a prime.

It is a d-powerful number, because it can be written as 6⁶ + 3¹² + 2¹¹ + 9⁵ + 4 + 7² .

It is a Duffinian number.

639247 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639257) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9508 + ... + 9574.

It is an arithmetic number, because the mean of its divisors is an integer number (48960).

2⁶³⁹²⁴⁷ is an apocalyptic number.

639247 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

639247 is a deficient number, since it is larger than the sum of its proper divisors (144113).

639247 is a wasteful number, since it uses less digits than its factorization.

639247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150.

The product of its digits is 9072, while the sum is 31.

The square root of 639247 is about 799.5292364886. The cubic root of 639247 is about 86.1435766434.

The spelling of 639247 in words is "six hundred thirty-nine thousand, two hundred forty-seven".