643747 has 8 divisors (see below), whose sum is σ = 723744. Its totient is φ = 568128.

The previous prime is 643729. The next prime is 643751. The reversal of 643747 is 747346.

643747 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643747 - 2⁷ = 643619 is a prime.

It is a d-powerful number, because it can be written as 6⁶ + 4² + 7² + 3¹² + 4⁸ + 7² .

It is a Duffinian number.

643747 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (643547) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 778 + ... + 1375.

It is an arithmetic number, because the mean of its divisors is an integer number (90468).

2⁶⁴³⁷⁴⁷ is an apocalyptic number.

643747 is a deficient number, since it is larger than the sum of its proper divisors (79997).

643747 is a wasteful number, since it uses less digits than its factorization.

643747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2189.

The product of its digits is 14112, while the sum is 31.

The square root of 643747 is about 802.3384572610. The cubic root of 643747 is about 86.3452410078.

The spelling of 643747 in words is "six hundred forty-three thousand, seven hundred forty-seven".