639601 has 2 divisors, whose sum is σ = 639602. Its totient is φ = 639600.

The previous prime is 639599. The next prime is 639631. The reversal of 639601 is 106936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 577600 + 62001 = 760^2 + 249^2 .

It is a cyclic number.

It is not a de Polignac number, because 639601 - 2¹ = 639599 is a prime.

Together with 639599, it forms a pair of twin primes.

639601 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (639631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319800 + 319801.

It is an arithmetic number, because the mean of its divisors is an integer number (319801).

2⁶³⁹⁶⁰¹ is an apocalyptic number.

It is an amenable number.

639601 is a deficient number, since it is larger than the sum of its proper divisors (1).

639601 is an equidigital number, since it uses as much as digits as its factorization.

639601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 25.

The square root of 639601 is about 799.7505861204. The cubic root of 639601 is about 86.1594751400.

The spelling of 639601 in words is "six hundred thirty-nine thousand, six hundred one".