505639 has 2 divisors, whose sum is σ = 505640. Its totient is φ = 505638.

The previous prime is 505633. The next prime is 505643. The reversal of 505639 is 936505.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 505639 - 2⁵ = 505607 is a prime.

505639 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (505633) 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 as a sum of consecutive naturals, namely, 252819 + 252820.

It is an arithmetic number, because the mean of its divisors is an integer number (252820).

2⁵⁰⁵⁶³⁹ is an apocalyptic number.

505639 is a deficient number, since it is larger than the sum of its proper divisors (1).

505639 is an equidigital number, since it uses as much as digits as its factorization.

505639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4050, while the sum is 28.

The square root of 505639 is about 711.0829768740. The cubic root of 505639 is about 79.6673163543.

The spelling of 505639 in words is "five hundred five thousand, six hundred thirty-nine".