642321 has 24 divisors (see below), whose sum is σ = 1010880. Its totient is φ = 391776.

The previous prime is 642281. The next prime is 642359. The reversal of 642321 is 123246.

It is a happy number.

642321 is a `hidden beast` number, since 642 + 3 + 21 = 666.

It is not a de Polignac number, because 642321 - 2¹⁹ = 118033 is a prime.

642321 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 642294 and 642303.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642321.

It is not an unprimeable number, because it can be changed into a prime (642361) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5950 + ... + 6056.

It is an arithmetic number, because the mean of its divisors is an integer number (42120).

2⁶⁴²³²¹ is an apocalyptic number.

It is an amenable number.

642321 is a deficient number, since it is larger than the sum of its proper divisors (368559).

642321 is a wasteful number, since it uses less digits than its factorization.

642321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165 (or 162 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 642321 is about 801.4493121839. The cubic root of 642321 is about 86.2814378150.

Adding to 642321 its reverse (123246), we get a palindrome (765567).

The spelling of 642321 in words is "six hundred forty-two thousand, three hundred twenty-one".