6643237 has 4 divisors (see below), whose sum is σ = 6723360. Its totient is φ = 6563116.

The previous prime is 6643229. The next prime is 6643249. The reversal of 6643237 is 7323466.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7323466 = 2 ⋅3661733.

It is a cyclic number.

It is not a de Polignac number, because 6643237 - 2³ = 6643229 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

6643237 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 6643199 and 6643208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6643337) 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, 39937 + ... + 40102.

It is an arithmetic number, because the mean of its divisors is an integer number (1680840).

Almost surely, 2^6643237 is an apocalyptic number.

It is an amenable number.

6643237 is a deficient number, since it is larger than the sum of its proper divisors (80123).

6643237 is an equidigital number, since it uses as much as digits as its factorization.

6643237 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80122.

The product of its digits is 18144, while the sum is 31.

The square root of 6643237 is about 2577.4477686269. The cubic root of 6643237 is about 187.9864653754.

The spelling of 6643237 in words is "six million, six hundred forty-three thousand, two hundred thirty-seven".