643673 has 4 divisors (see below), whose sum is σ = 650148. Its totient is φ = 637200.

The previous prime is 643661. The next prime is 643681. The reversal of 643673 is 376346.

643673 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 can be written as a sum of positive squares in 2 ways, for example, as 582169 + 61504 = 763^2 + 248^2 .

It is a cyclic number.

It is not a de Polignac number, because 643673 - 2¹² = 639577 is a prime.

It is a d-powerful number, because it can be written as 6 + 4⁸ + 6⁶ + 3³ + 7 + 3¹² .

It is a Duffinian number.

It is a Curzon number.

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, 3086 + ... + 3287.

It is an arithmetic number, because the mean of its divisors is an integer number (162537).

2⁶⁴³⁶⁷³ is an apocalyptic number.

It is an amenable number.

643673 is a deficient number, since it is larger than the sum of its proper divisors (6475).

643673 is a wasteful number, since it uses less digits than its factorization.

643673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6474.

The product of its digits is 9072, while the sum is 29.

The square root of 643673 is about 802.2923407337. The cubic root of 643673 is about 86.3419323619.

The spelling of 643673 in words is "six hundred forty-three thousand, six hundred seventy-three".