642623 has 2 divisors, whose sum is σ = 642624. Its totient is φ = 642622.

The previous prime is 642613. The next prime is 642673. The reversal of 642623 is 326246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642623 - 2¹² = 638527 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642613) 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, 321311 + 321312.

It is an arithmetic number, because the mean of its divisors is an integer number (321312).

2⁶⁴²⁶²³ is an apocalyptic number.

642623 is a deficient number, since it is larger than the sum of its proper divisors (1).

642623 is an equidigital number, since it uses as much as digits as its factorization.

642623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1728, while the sum is 23.

The square root of 642623 is about 801.6376987143. The cubic root of 642623 is about 86.2949580079.

Adding to 642623 its reverse (326246), we get a palindrome (968869).

The spelling of 642623 in words is "six hundred forty-two thousand, six hundred twenty-three".