643623 has 4 divisors (see below), whose sum is σ = 858168. Its totient is φ = 429080.

The previous prime is 643619. The next prime is 643633. The reversal of 643623 is 326346.

643623 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643623 - 2² = 643619 is a prime.

It is a super-2 number, since 2×643623² = 828501132258, which contains 22 as substring.

It is a D-number.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 643593 and 643602.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643623.

It is not an unprimeable number, because it can be changed into a prime (643633) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107268 + ... + 107273.

It is an arithmetic number, because the mean of its divisors is an integer number (214542).

2⁶⁴³⁶²³ is an apocalyptic number.

643623 is a deficient number, since it is larger than the sum of its proper divisors (214545).

643623 is a wasteful number, since it uses less digits than its factorization.

643623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214544.

The product of its digits is 2592, while the sum is 24.

The square root of 643623 is about 802.2611794173. The cubic root of 643623 is about 86.3396966467.

Adding to 643623 its reverse (326346), we get a palindrome (969969).

The spelling of 643623 in words is "six hundred forty-three thousand, six hundred twenty-three".