642799 has 2 divisors, whose sum is σ = 642800. Its totient is φ = 642798.

The previous prime is 642797. The next prime is 642809. The reversal of 642799 is 997246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642799 - 2¹ = 642797 is a prime.

Together with 642797, it forms a pair of twin primes.

It is a d-powerful number, because it can be written as 6² + 4² + 7⁶ + 2¹⁹ + 9² + 9³ .

642799 is a lucky number.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321399 + 321400.

It is an arithmetic number, because the mean of its divisors is an integer number (321400).

2⁶⁴²⁷⁹⁹ is an apocalyptic number.

642799 is a deficient number, since it is larger than the sum of its proper divisors (1).

642799 is an equidigital number, since it uses as much as digits as its factorization.

642799 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 37.

The square root of 642799 is about 801.7474664756. The cubic root of 642799 is about 86.3028353722.

It can be divided in two parts, 642 and 799, that added together give a palindrome (1441).

The spelling of 642799 in words is "six hundred forty-two thousand, seven hundred ninety-nine".