523639 has 2 divisors, whose sum is σ = 523640. Its totient is φ = 523638.

The previous prime is 523637. The next prime is 523657. The reversal of 523639 is 936325.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 523639 - 2¹ = 523637 is a prime.

Together with 523637, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (523631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 261819 + 261820.

It is an arithmetic number, because the mean of its divisors is an integer number (261820).

2⁵²³⁶³⁹ is an apocalyptic number.

523639 is a deficient number, since it is larger than the sum of its proper divisors (1).

523639 is an equidigital number, since it uses as much as digits as its factorization.

523639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4860, while the sum is 28.

The square root of 523639 is about 723.6290486154. The cubic root of 523639 is about 80.6016616142.

Subtracting 523639 from its reverse (936325), we obtain a triangular number (412686 = T₉₀₈).

The spelling of 523639 in words is "five hundred twenty-three thousand, six hundred thirty-nine".